Solely depend on me (6)
I believe the answer is:
merely
'solely' is the definition.
(thesaurus)
'depend on me' is the wordplay.
'depend' becomes 'rely' (to depend on someone is to rely on them).
'on' says to put letters next to each other.
'rely' after 'me' is 'MERELY'.
(Other definitions for merely that I've seen before include "Just one" , "'Only, and nothing more (6)'" , "Simply - only" .)