Taking off hat having dropped one pin (7)
I believe the answer is:
skittle
'pin' is the definition.
(I know that skittle is a type of pin)
'taking off hat having dropped one' is the wordplay.
'taking off' becomes 'skit' (a skit might mock someone or take them off).
'hat' becomes 'tile' (old-fashioned term for a hat).
'having dropped' suggests deleting specific letters.
'one' becomes 'i' (Roman numeral).
'tile' with 'i' removed is 'tle'.
'skit'+'tle'='SKITTLE'
(Other definitions for skittle that I've seen before include "Pin to be knocked down" , "Upset" , "Knock down" , "Pin in ninepins" , "one keeps getting knocked down" .)