gù
to become solid
Phonosemantic compound. 囗 represents the meaning and 古 represents the sound.
Evolution

Bronze script
Late Warring States (~250 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Eastern Han dynasty (25-220 AD)Regular script
ModernDefinitions
gù
to become solid, solidify; strength; hard; strong; solid; sure; assuredly; undoubtedly; of course; indeed; admittedly
Component uses
Sources