Strong iron wings under pressure (7)
I believe the answer is:
intense
'strong' is the definition.
(similar in meaning)
'iron wings under pressure' is the wordplay.
'wings' suggests removing the centre (the wings or edge letters of the word are used).
'under pressure' becomes 'tense' (I've seen this before).
'iron' with its centre removed is 'in'.
'in'+'tense'='INTENSE'
(Other definitions for intense that I've seen before include "Of extreme force" , "Showing strong feelings or opinions" , "'Ardent, forceful (7)'" , "amplified?" , "say, description of campers?" .)