About to drop stick (6)
I believe the answer is:
cleave
'stick' is the definition.
(cleave can mean to stick to something)
'about to drop' is the wordplay.
'about' becomes 'c' (abbreviation for circa).
'to drop' becomes 'leave' (leave can mean to drop or discard).
'c'+'leave'='CLEAVE'
(Other definitions for cleave that I've seen before include "Join or split" , "Split or cling to" , "Stick fast; split" , "Adhere - or chop as with axe" , "Fissure" .)