Declared it could be worse (5)
I believe the answer is:
swore
'declared' is the definition.
(swearing is a kind of declaring)
'it could be worse' is the wordplay.
'it could be' indicates anagramming the letters (the same letters could be an anagram).
'worse' with letters rearranged gives 'SWORE'.
(Other definitions for swore that I've seen before include "Blasphemed" , "Uttered profanities or avowed" , "used bad language" , "Took oath or cursed" .)