Gloomy German on the edge (4)
I believe the answer is:
grim
'gloomy' is the definition.
(thesaurus)
'german on the edge' is the wordplay.
'german' becomes 'g' (abbreviation).
'on' says to put letters next to each other.
'the edge' becomes 'rim' (rim is a kind of edge).
'g'+'rim'='GRIM'
(Other definitions for grim that I've seen before include "Stern and unsmiling" , "Dire" , "Dark, depressing" , "(Of humour) black; unappealing, depressing" , "looking black" .)