say it: TAHY-tuhn
tighten is a verb meaning "make tight or tighter". It carries 4 recorded senses.
severely restrict in scope or extent
“tighten the rules”
“stiffen the regulations”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for tighten come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.