WordWeb Online

1. Attach something somewhere by means of nails
   - nail
    
2. Define clearly
   "I cannot nail down the rules for this game";
   - pin down, peg down [informal], narrow down, narrow, specify
    
3. Make final; put the last touches on; put into final form
   "let's nail down the proposal";
   - finalize, finalise [Brit], settle
    
4. [informal] Succeed in obtaining a position
   "He nailed down a spot at Harvard";
   - nail [informal], peg [informal]

Derived forms: nailing down, nails down, nailed down

Type of: attach, bring home the bacon [informal], come through, come up trumps [Brit, informal], deliver the goods, determine, end, succeed, terminate, turn up trumps [Brit, informal], win