Instrument carried by hobo everywhere (4)
I believe the answer is:
oboe
'instrument' is the definition.
(type of musical instrument)
'carried by hobo everywhere' is the wordplay.
'carried by' indicates a hidden word.
'OBOE' is hidden in the letters of 'hobo everywhere'.
(Other definitions for oboe that I've seen before include "Slender double-reed instrument" , "music producer" , "Double-reed woodwind" , "Orchestral piece" , "Double-reeded woodwind instrument" .)