jiē
sigh
Phonosemantic compound. 口 represents the meaning and 差 represents the sound.
Evolution

Seal script
Shuowen (~100 AD)
Clerical script
Eastern Han dynasty (25-220 AD)
Clerical script
Eastern Han dynasty (25-220 AD)
Clerical script
Cao Wei (Three Kingdoms: 222-280 AD)Regular script
ModernDefinitions
Sources