Almost respect a trainee officer (7)
I believe the answer is:
admiral
'officer' is the definition.
(admiral is a kind of officer)
'almost respect a trainee' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'respect' becomes 'admire' (admiring is a kind of respecting).
'a trainee' becomes 'al' (I am not sure about this - if you are sure you should believe this answer much more).
'admire' with its final letter taken off is 'admir'.
'admir'+'al'='ADMIRAL'
(Other definitions for admiral that I've seen before include "Chief commander of fleet" , "(White or red) butterfly" , "Commander of the fleet or butterfly" , "Highest naval rank" , "Navy rank" .)