Trough into which goes a head (7)
I believe the answer is:
manager
'head' is the definition.
(manager is a kind of head)
'trough into which goes a' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for manager that I've seen before include "Boss" , "Sports team controller" , "One running a shop, industry etc" , "who tries to cope?" , "Executive or controller" .)