Keen to keep word 'sex' occasional (12)
I believe the answer is:
intermittent
'occasional' is the definition.
(I've seen this before)
'keen to keep word sex' is the wordplay.
I cannot quite understand how this works, but
'word' could be 'term' (term is a kind of word) and 'term' is present in the answer.
'sex' could be 'it' (a common euphemism) and 'it' is located in the answer.
'keen' could be 'intent' (I've seen this before) and 'intent' is located in the leftover letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for intermittent that I've seen before include "On-and-off" , "Irregular" , "Occurring irregularly" , "Not continuous or steady" , "Spasmodic" .)