Antithetic (or its more common form, antithetical)

[White Wolf]

Antithetic (or its more common form, antithetical) means directly opposite, contradictory, or sharply contrasted in character, purpose, or nature; it describes something fundamentally at odds with something else, like good and evil or a vegetarian diet and eating meat. It comes from Greek, meaning "to set in opposition," and is used to show extreme difference or opposition, often in formal contexts.

Key Meanings
Directly Opposite: Something that is the complete reverse of something else.
Contradictory: In conflict with or unable to coexist with another idea or belief.
Sharply Contrasted: Very different in quality, form, or nature.

Examples in Use
"A culture of violence is antithetical to peace".
"His rebellious spirit was antithetic to the rigid rules".
"The two theories are antithetic in their conclusions".

Related Term
Antithesis: The literary device of contrasting ideas (like "action, not words") or the direct opposite itself (e.g., "love is the antithesis of hate").