The phrase "a sinister line" is correct and usable in written English.
It can be used to describe a line of text, dialogue, or even a physical line that conveys a sense of evil or malevolence.
Example: "The author crafted a sinister line that sent chills down the reader's spine, hinting at the dark fate awaiting the protagonist."
Alternatives: "an ominous line" or "a malevolent line".
A fox ventures forth to forage for berries on the snow-covered land, and a sinister line of starved black crows converges to attack him.
A sinister line of drummers in military tunics, their faces invisible in the half-dark, the crash and volley of their percussion obliterating all thought and dissent.
After all ninjas are dead, say a sinister line and walk away.
The refrain is simultaneously inclusive and ominous, as it's repeatedly howled over a sinister bass line.
However, to track a 20-year-old citizen with no ties to anything remotely dangerous and then treat the activity like a joke ("Don't worry, you're boring" is probably the most sinister line I've heard in years) is an affront to the laws they are sworn to uphold.
That excitement is somewhat curbed by mummy packing the kids off with the genuinely sinister line: "Remember.
Or you might prefer the $70 electronic Intelli-table being advertised on TV with the sinister line, "Smart parents want to give their children the best possible start on learning".
This sinister line rings through Suspiria, increasingly true with every act.
In "Soul Kitchen," Rickey takes a consulting gig for an haute soul food restaurant on a spooky gambling boat on Lake Pontchartrain, whose backers are a pill-pushing doctor and a sinister old-line Carnival boss.
In hard-boiled novels of the 30's and 40's, the American highway is a sinister place lined with greasy spoons and fleabag tourist camps and populated by felons and fornicators whose original sin, it's suggested, is transience.
If not, my recollection of his most fantastically sinister lines will always come in the voice of Bertie Wooster.
