HSK3
fǒu, pǐ
not
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.
不 Sound Meaning component
bù
no
口 Distinguishing component
kǒu
mouth
Added later when the character started to mean "not" and to distinguish from 不.
Bronze script
Seal script
Clerical script
Regular script
否
fǒu
not, no, negative; final particle; to negate; to deny; not
pǐ
clogged; evil
是否
if
否则
if not
能否
whether or not
否认
to deny
Meaning component in 1 character (1 verified)
咅
Sound component in 2 characters (1 verified)
咅 痞
Academia Sinica
Make Me a Hanzi
Unicode
Baxter-Sagart
Dong Chinese
CC-CEDICT
SUBTLEX-CH
MTSU Chinese text computing
漢語多功能字庫
李学勤《字源》p.94-95