Taps engaging American's bottom and robes (8)
I believe the answer is:
cassocks
'robes' is the definition.
(cassock is a kind of robe)
'taps engaging american's bottom' is the wordplay.
I cannot quite see how this works, but
'american's' could be 'as' (common abbreviation - e.g. in organisation names) and 'as' is present in the answer.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for cassocks that I've seen before include "Black vestments worn by priests" , "robes" , "Black frocks worn by priests" , "Black vestments for a priest" , "Full-length garments for the clergy" .)