1. (

• tighten ,
• fasten

) make tight or tighter; "Tighten the wire" ;

2. (

• tighten

) become tight or tighter; "The rope tightened" ;

3. (

• stiffen ,
• tighten ,
• tighten_up ,
• constrain

) severely restrict in scope or extent; "tighten the rules"; "stiffen the regulations" ;

4. (

• reduce ,
• tighten ,

) narrow or limit; "reduce the influx of foreigners" ;