It can be good or nasty! (4)
I believe the answer is:
turn
(Other definitions for turn that I've seen before include "Move in a new direction" , "Revolve; act" , "Sour" , "(Of tide) change from flood to ebb" , "fit" .)
I believe the answer is:
turn
(Other definitions for turn that I've seen before include "Move in a new direction" , "Revolve; act" , "Sour" , "(Of tide) change from flood to ebb" , "fit" .)