Strong old soldier captures macho blokes (8)
I believe the answer is:
vehement
'strong' is the definition.
(I've seen this before)
'old soldier captures macho blokes' is the wordplay.
'old soldier' becomes 'vet' (I've seen this before).
'captures' is an insertion indicator.
'macho blokes' becomes 'hemen' (I can't justify this - if you can you should give a lot more credence to this answer).
'vet' enclosing 'hemen' is 'VEHEMENT'.
Can you help me to learn more?
(Other definitions for vehement that I've seen before include "Zealously forceful" , "Of speech, intense and forceful" , "Forcible" , "Vigorously emphatic" , "Showing strong feeling, intense in speech" .)