From Longman Dictionary of Contemporary Englishtightentight‧en /ˈtaɪtn/ ●●○ (also tighten up) verb 1 [transitive]TIGHT to close or fasten something firmly by turning it OPP loosen Tighten the screws firmly. I’d put the new tyre on, but I hadn’t tightened up the wheel.2 [intransitive, transitive]TIGHT if you tighten a rope, wire etc, or if it tightens, it is stretched or pulled so that it becomes tight When you tighten guitar strings, the note gets higher. The rope tightened around his body.3 HBHHURT/CAUSE PAIN[intransitive, transitive] to become stiff or make a part of your body become stiff OPP relax His mouth tightened into a thin, angry line. Tighten up the muscles of both arms.4 → tighten your grip/hold on something5 [transitive]STRICT to make a rule, law, or system more strict OPP relax Efforts to tighten the rules have failed.tighten up on something a range of measures to tighten up on illegal share dealing6 → tighten your belt7 → tighten the screws (on somebody)8 [intransitive] American English if a race or competition tightens, the distance between the competitors becomes smaller He expects the presidential race to tighten. → tighten up→ See Verb table
Examples from the Corpustighten• I think the fan belt needs to be tightened.• The rope tightened and Steve was pulled off balance.• The bill would tighten existing gun-control regulations.• Judy's lips tightened in a thin smile.• As though to tighten it a hand came to rest on hers.• As the investigation continued into June, Dunlap could feel the vise tighten, squeezing out any possibility of hope.• They believe moves to tighten the gun laws even further could result in even more firearms flooding the black market.• She bent down and tightened the muzzle on the dog.• He changed the spanner for one the correct size and tightened the nut.• I need to tighten the screw on my glasses.• Tighten the screws gradually until the wheel is firmly in place.• The estate owners tightened their systems, with a view to greater productivity - new breeds, crops, implements and methods.• I felt my stomach tighten, unreason bubbling, rising.• Tighten up the lid on that juice before you put it away.• But Hill hurt a hamstring on the return, and had to leave the game after his leg tightened up.• The cross-fence would be finished sometime today, once we got all the wires pulled out and tightened up.• Tighten your stomach muscles and hold for three seconds.tighten up on something• Every now and then, his knees tighten up on him.• Thus, in times of slack demand it is not uncommon to find managements tightening up on industrial discipline.• Green wants teachers to tighten up on student attendance.