Predator moved to show sign of distress (8)
I believe the answer is:
teardrop
'sign of distress' is the definition.
(I've seen this before)
'predator moved' is the wordplay.
'moved' indicates anagramming the letters.
'predator' with letters rearranged gives 'TEARDROP'.
'to show' is the link.
(Other definitions for teardrop that I've seen before include "pearl" , "It comes from the lachrymal gland" , "one running away from viewer" , "spot of grief" , "Bit of salty moisture" .)