The illicit affair of removing pests from mousetraps (5)
I believe the answer is:
amour
'the illicit affair' is the definition.
'amour' can be an answer for 'affair' ('amour' can be a synonym of 'affair'). I'm not certain of the 'the illicit' bit.
'removing pests from mousetraps' is the wordplay.
'removing' indicates an anagram (moving the letters again).
'from' suggests deleting specific letters.
'mousetraps' with 'pests' taken away is 'moura'.
'moura' with letters rearranged gives 'AMOUR'.
'of' is the link.
Can you help me to learn more?
(Other definitions for amour that I've seen before include "Romantic liaison" , "Romantic affair" , "Illicit love" , "Love-affair" , "French lover" .)