Criminal does join, dead grim (8)
I believe the answer is:
desolate
'grim' is the definition.
Both the definition and answer are adjectives. Maybe they are linked in a way I don't understand?
'criminal does join dead' is the wordplay.
'criminal' indicates an anagram.
'join' says to put letters next to each other.
'dead' becomes 'late' (similar in meaning).
'does' anagrammed gives 'deso'.
'deso'+'late'='DESOLATE'
Can you help me to learn more?
(Other definitions for desolate that I've seen before include "Miserable" , "'Deserted, wretched (8)'" , "Wretched, unhappy" , "Forlorn and unhappy" , "Forlorn and abandoned" .)