to negate; to deny; to reject; negative (answer); negation
否 (fǒu) · 7 strokes
Originally the same character as 不. Distinguishing component 口 was added later to the character when it took on the meaning "not". 不 represents the sound.
定 (dìng) · 8 strokes
Phonosemantic compound. 宀 represents the meaning and 正 represents the sound.