Puzzle out (5)
'puzzle out' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for solve that I've seen before include "Complete crossword" , "Clear up a mystery" , "Unscramble" , "Deal with (a problem)" , "Explain (a mystery)" .)
(Other definitions for suss that I've seen before include "Figure (out)" , "Work (out) (slang)" , "Behaviour interesting police" , "Discover (slang)" , "sharpness of mind" .)