Hemmed in by strangers, I complain so! (3)
I believe the answer is:
sic
'so' is the definition.
('so' in Latin)
'hemmed in by strangers i complain' is the wordplay.
'hemmed in by' indicates a hidden word.
'SIC' is hidden in the letters of 'strangers i complain'.
(Other definitions for sic that I've seen before include "Quoted exactly as in the original; so" , "Thus in Corsica" , "Thus among musicians" , "(Of quoted word) exactly so" , "Word to call attention to a quoted mistake" .)