Concealment of a mountain sheep, bouncing about in enclosure (10)
I believe the answer is:
camouflage
'concealment' is the definition.
(camouflage is a kind of concealment)
'mountain sheep bouncing about in enclosure' is the wordplay.
I cannot quite understand how this works, but
'mountain' could be 'm' (geographical abbreviation) and 'm' is located in the answer.
'about' could be 'ca' (circa) and 'ca' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'of a' acts as a link.
Can you help me to learn more?
(Other definitions for camouflage that I've seen before include "blind" , "Means of disguise" , "Method of blending in fine" , "Disguise by use of colour, patterns etc" , "Green and brown on a green and brown background, say?" .)