Solver's ending with nothing? Obtain source of synonyms (5)
I believe the answer is:
roget
'source of synonyms' is the definition.
(as in Roget's Thesaurus)
'solver's ending with nothing? obtain' is the wordplay.
'ending' indicates one should take the final letters.
'with nothing?' becomes 'o' (I've seen this in other clues).
'obtain' becomes 'get' ('get' can be a synonym of 'obtain').
The last letter of 'solver' is 'r'.
'r'+'o'+'get'='ROGET'
(Other definitions for roget that I've seen before include "Scholar remembered for his Thesaurus" , "English physician and thesaurus compiler, d. 1869" , "Thesaurus creator" , "Thesaurus constructor" , "Author of popular English Thesaurus" .)