Bobby needs a cool head at work (3)
I believe the answer is:
cop
'bobby' is the definition.
(thesaurus)
'a cool head at work' is the wordplay.
'head' indicates taking the first letters.
'at work' becomes 'op' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'cool' is 'c'.
'c'+'op'='COP'
'needs' is the link.
Can you help me to learn more?
(Other definitions for cop that I've seen before include "busy" , "Police officer (informal)" , "Policeman (colloq.)" , "Get" , "Policeman (informal)" .)