Used and loved by millions
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
serious in thought
Grammar usage guide and real-world examplesUSAGE SUMMARY
The phrase "serious in thought" is correct and usable in written English.
You can use it to describe someone who is deeply contemplating or reflecting on a matter with a focused and earnest mindset. Example: "During the meeting, she appeared serious in thought, carefully considering the implications of the proposed changes."
✓ Grammatically correct
News & Media
Science
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
1 human-written examples
In the same context, Ross also wrote: "Jazz was intuitive, intimate, collaborative; it was serious in thought but playful in execution".
News & Media
Human-verified similar examples from authoritative sources
Similar Expressions
56 human-written examples
As in, thought-less.
News & Media
For an entire match, she was deep in serious thought.
News & Media
There's something those would-be engineers and scientists aren't getting; we might call it training in serious thought, another of those "intangibles" that escape the net of numerical assessment.
News & Media
There is a murmur among the crowd, a running commentary of surprise or indignation or awe about this or that offering, as if everyone were at least engaged in serious thought about the possibility of acquiring one or another residence.
News & Media
It has been my experience that about the only time we engage in serious thought about the implications of military service is when a member of the armed forces who is in some way connected to one of our congregations is either seriously injured or killed.
News & Media
Without using the word 'philosophy,' either here or anywhere else in Harry, Lipman shows Harry engaged in serious philosophical thought, "thinking about thinking".
Science
Neglect of the distinction between (4) and (5) can result in serious confusion of thought; in ordinary speech it is frequently unclear whether someone who denies that the ϕ is ψ is conceding that exactly one thing is ϕ but denying that it is ψ, or denying that exactly one thing is ϕ.
Encyclopedias
It is commonplace to hear that "identity" is a term in serious crisis in feminist thought, and that feminist praxis must move beyond identity politics (Dean 1996).
Science
Family Income: Among American adults in 2013, serious suicidal thoughts occurred in: 6.6percentt of those from family incomes below the Federal poverty level, 4.7percentt of those with family incomes between 100 and 199percentt of the Federal poverty level, and 3.1percentt of those with annual family incomes at 200percentt or more of the Federal poverty level.
News & Media
In 2010, significant predictors of serious suicidal thoughts in a multivariate model were low subjective well-being (OR 0.68; 95% CI 0.52-0.90), porr or average self-rated health (2.36; 1.25-4.45) and high psychosocial work stress (1.92; 1.06-3.46), controlled for age, gender, speciality and job satisfaction.
Science
Expert writing Tips
Best practice
Use "serious in thought" to describe a deliberate and earnest consideration of a topic, especially when emphasizing the intellectual rigor involved.
Common error
Avoid using "serious in thought" when simply describing someone who is thinking; reserve it for situations where the thoughtfulness is profound or has significant implications.
Source & Trust
89%
Authority and reliability
4.3/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "serious in thought" functions as a descriptive adjective phrase, modifying a noun to indicate a state of deep and earnest contemplation. It highlights the intensity and significance of the thinking process, as supported by Ludwig.
Frequent in
News & Media
45%
Science
35%
Formal & Business
10%
Less common in
Encyclopedias
5%
Wiki
3%
Reference
2%
Ludwig's WRAP-UP
In summary, "serious in thought" is a grammatically sound phrase, as validated by Ludwig, used to depict a state of deep, earnest contemplation. Although relatively uncommon, the phrase finds its primary use in news media and scientific writing to emphasize the weight and intellectual rigor of the thinking process. While alternatives like "deep in contemplation" or simply "thoughtful" exist, "serious in thought" specifically conveys the depth and significance of the reflection, making it a valuable descriptor when precision is needed. The expert rating reflects the phrase's correct usage and source authority, tempered by its limited frequency.
More alternative expressions(6)
Phrases that express similar concepts, ordered by semantic similarity:
deep in contemplation
Emphasizes the depth of thought, focusing on the state of contemplating something profoundly.
engrossed in thought
Highlights the level of absorption in one's thoughts, suggesting a complete focus.
lost in thought
Suggests a disconnection from the surroundings due to intense thinking.
thoughtful
A simpler adjective describing someone who is prone to thinking deeply.
reflective
Describes a tendency to ponder and consider things carefully.
pondering deeply
Focuses on the act of considering something with great attention.
meditative
Implies a calm, sustained focus on inner thoughts, similar to a meditative practice.
given to reflection
Describes a person who often thinks about past events or ideas.
intellectually engaged
Highlights the mental activity and focus on intellectual matters.
absorbed in consideration
Stresses the complete absorption in the process of thinking something over.
FAQs
How can I use "serious in thought" in a sentence?
You can use "serious in thought" to describe a person or character who is deeply contemplating or reflecting on something, such as, "The professor appeared "serious in thought" as she considered the implications of the new research."
What are some alternatives to "serious in thought"?
Alternatives to "serious in thought" include "deep in contemplation", "engrossed in thought", or simply "thoughtful", depending on the specific nuance you want to convey.
Is it better to say "serious in thought" or "deep in thought"?
Both "serious in thought" and "deep in thought" are grammatically correct. "Deep in thought" is more common and generally describes someone who is thinking intently, while "serious in thought" implies a more grave or earnest consideration.
When is it appropriate to use the phrase "serious in thought"?
Use "serious in thought" when you want to emphasize that someone is not just casually thinking, but is engaged in deep, earnest reflection, often about something important or weighty.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
89%
Authority and reliability
4.3/5
Expert rating
Real-world application tested