Wordnet 3.0
VERB (1)
1. 
 fall or sink heavily; 
- Example: "He slumped onto the couch"- Example: "My spirits sank"[syn: slump, slide down, sink]
WordNet (r) 3.0 (2006):
slide down
    v 1: fall or sink heavily; "He slumped onto the couch"; "My
         spirits sank" [syn: slump, slide down, sink]