The smoke when Joe reverses in the car (5)
I believe the answer is:
cigar
'the smoke' is the definition.
(I've seen this before)
'joe reverses in the car' is the wordplay.
'joe' becomes 'gi' (GI Joe).
'reverses' says the letters should be written in reverse.
'in the' means one lot of letters goes inside another.
'gi' reversed gives 'ig'.
'ig' going inside 'car' is 'CIGAR'.
'when' is the link.
(Other definitions for cigar that I've seen before include "Roll of tobacco leaves for smoking" , "Tobacco product" , "Close, but no ___ !" , "Roll of cured tobacco" , "Big roll of tobacco" .)