Fancied a military man in tight denim (8)
I believe the answer is:
imagined
'fancied' is the definition.
(I've seen this before)
'a military man in tight denim' is the wordplay.
'military man' becomes 'gi'.
'in' means one lot of letters goes inside another.
'tight' indicates an anagram (tight can mean drunk).
'a'+'gi'='agi'
'denim' anagrammed gives 'imned'.
'agi' inserted within 'imned' is 'IMAGINED'.
(Other definitions for imagined that I've seen before include "Formed a mental image" , "Conjured up in the mind" , "Envisaged" , "Supposed" , "Created mentally" .)