Undoing blouse embracing masculine clot (7)
I believe the answer is:
embolus
'clot' is the definition.
(embolus is a kind of clot)
'undoing blouse embracing masculine' is the wordplay.
'undoing' is an anagram indicator.
'embracing' indicates putting letters inside.
'masculine' becomes 'm'.
'blouse' anagrammed gives 'ebolus'.
'ebolus' enclosing 'm' is 'EMBOLUS'.
(Other definitions for embolus that I've seen before include "Circulatory problem" , "Blood clot" .)