Behind, like with rent? That's awkward (6)
I believe the answer is:
astern
'behind' is the definition.
(at the back or behind of a ship)
'like with rent? that's awkward' is the wordplay.
'like' becomes 'as'.
'with' means one lot of letters go next to another.
'that's awkward' indicates an anagram.
'rent' anagrammed gives 'tern'.
'as'+'tern'='ASTERN'
(Other definitions for astern that I've seen before include "following behind vessel" , "(In relation to ship) behind" , "Behind (a boat)" , "Behind the back of a ship" , "at the vessel's rear" .)