Creatures without true worries (5)
I believe the answer is:
cares
'worries' is the definition.
(I've seen this before)
'creatures without true' is the wordplay.
'without' is a deletion indicator.
'creatures' with 'true' removed is 'CARES'.
(Other definitions for cares that I've seen before include "Worries, anxieties" , "Minds" , "Feels interest or concern" , "Has concerns or interest" .)