Definition of Tighten

Verb: tighten tI-t(u)n

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