Wordnet 3.0
ADJECTIVE (2)
1. 
 lacking teeth; 
- Example: "most birds are toothless"- Example: "a toothless old crone"2. 
 lacking necessary force for effectiveness; 
- Example: "a toothless piece of legislation"
The Collaborative International Dictionary of English v.0.48:
Toothless \Tooth"less\, a.
   Having no teeth. --Cowper.
   [1913 Webster]
WordNet (r) 3.0 (2006):
toothless
    adj 1: lacking teeth; "most birds are toothless"; "a toothless
           old crone" [ant: toothed]
    2: lacking necessary force for effectiveness; "a toothless piece
       of legislation"