The phrase "against my principles" is correct and usable in written English.
You can use it when expressing that an action or decision conflicts with your personal beliefs or values.
Example: "I cannot support that initiative because it goes against my principles."
Alternatives: "contrary to my values" or "in conflict with my beliefs."
Mr. Haouari said he quit the party the following April, claiming the F.I.S. had used violence to achieve its ends, which he said was against "my principles and religion".
It's a wrench to give up but it would be against my principles to continue".
"This is against my principles — and illegal," he said of the Russian military's hacking effort.
The idea of some bloke looking me up and down and telling me off for not shaving properly went totally against my principles.
Rick Santorum just offered up what may be the evening's most wince-inducing moment: he declared that he had voted for President George W. Bush's No Child Left Behind education law even though "it was my against my principles".
When the great Radio 1 dinosaur cull of 1993 took place, the Hairy Cornflake was appalled, informing his listeners that "changes are being made here which go against my principles, and I just cannot agree with them".
She recalled that he nodded, and replied: "It goes against all my principles.
"I'm a conservative Republican, and this goes against all my principles," said Brian Coppola, the chairman of the Board of Supervisors of Robinson Township, in Washington County west of Pittsburgh.
In saying that, I'm going against all my principles and my love of Wenger – I think Arsenal are out of the top four.
"I never gave anyone my number, so it went against all my principles, and guess what, after I gave him my number, he still waited five days to call me".
However, he refused to accept the offer and said to his wife, "It goes against all my principles.
