WordWeb Online

1. Make tight or tighter
   "Tighten the wire";
   - fasten
    
2. Become tight or tighter
   "The rope tightened"
    
3. (of laws or regulations) make more restrictive, or impose greater penalties
   "Tighten the rules"; "tighten up the regulations";
   - stiffen, tighten up, constrain
    
4. Narrow or limit
   "tighten the influx of foreigners";
   - reduce

Sounds like: ties, ighten, titan

Derived forms: tightened, tightens, tightening

Type of: alter, bound, change, confine, limit, modify, restrain, restrict, throttle, trammel