Ceremonial cleansing taking place in military washroom, perhaps? (8)
I believe the answer is:
ablution
'ceremonial cleansing' is the definition.
'ablution' can be an answer for 'cleansing' (ablution is a kind of cleansing). I'm unsure of the 'ceremonial' bit.
'taking place in military washroom perhaps?' is the wordplay.
I cannot really understand how this works, but
'taking' could be 'on' (eg one taking drugs is 'on' drugs) and 'on' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ablution that I've seen before include "About nil (anag.)" , "Toilet facility" , "Ceremonial washing of hands" , "Ritual washing in church" , "Washing process" .)