Poor angler has right of course to elaborate (7)
I believe the answer is:
enlarge
'elaborate' is the definition.
(I know that elaborate can be written as enlarge)
'poor angler has right of course' is the wordplay.
'poor' indicates an anagram.
'has' means one lot of letters go next to another.
'right of' suggests the final letters (letter on the rightmost end of the word).
The last letter of 'course' is 'e'.
'angler' is an anagram of 'enlarg'.
'enlarg'+'e'='ENLARGE'
'to' is the link.
(Other definitions for enlarge that I've seen before include "Gleaner (anag.)" , "Make big" , "Make bigger, say photo" , "Expatiate" , "Widen" .)