Musing male in area covered by tiny bit of litter? (8)
I believe the answer is:
ruminant
'musing' is the definition.
(both can mean thinking)
'male in area covered by tiny bit of litter?' is the wordplay.
'male' becomes 'm' (common abbreviation).
'area' becomes 'a' (maths abbreviation).
'covered by' means one lot of letters goes inside another.
'tiny bit of litter?' becomes 'runt' (runt of the litter).
'm'+'in'+'a'='mina'
'mina' placed within 'runt' is 'RUMINANT'.
(Other definitions for ruminant that I've seen before include "contemplating" , "Cud-chewing mammal" , "Animal that chews the cud" , "One chews the cud" , "Animal chewing cud" .)