Witty remark from heartless man reversing into luggage compartment (3,3)
I believe the answer is:
bon mot
'witty remark' is the definition.
(I've seen this before)
'heartless man reversing into luggage compartment' is the wordplay.
'heartless' means to remove the middle letters.
'reversing' says the letters should be written backwards.
'into' indicates putting letters inside.
'luggage compartment' becomes 'boot' ('boot' can be a synonym of 'luggage compartment').
'man' with its middle removed is 'mn'.
'mn' reversed gives 'nm'.
'nm' inserted within 'boot' is 'BON MOT'.
'from' is the link.
(Other definitions for bon mot that I've seen before include "term of French, it's appropriate to say" , "The right or apposite word - in France" , "Apt or witty remark - in France" , "Witty words" , "Witticism" .)