Disastrous time with Craig at sea (6)
I believe the answer is:
tragic
'disastrous' is the definition.
(thesaurus)
'time with craig at sea' is the wordplay.
'time' becomes 't'.
'with' says to put letters next to each other.
'at sea' indicates an anagram.
'craig' anagrammed gives 'ragic'.
't'+'ragic'='TRAGIC'
(Other definitions for tragic that I've seen before include "Shocking" , "heartbreaking" , "Deeply distressing" , "Intensely sad and distressing" , "Pitiable" .)