- characterized by rigor; rigidly severe or harsh, as people, rules, or discipline: rigorous laws.
- severely exact or accurate; precise: rigorous research.
- (of weather or climate) uncomfortably severe or harsh; extremely inclement.
- Logic, Mathematics. logically valid.
- characterized by or proceeding from rigour; harsh, strict, or severerigorous discipline
- severely accurate; scrupulousrigorous book-keeping
- (esp of weather) extreme or harsh
- maths logic (of a proof) making the validity of the successive steps completely explicit
late 14c., from Old French rigorous (13c., Modern French rigoureux), from Medieval Latin rigorosus, from Latin rigor (see rigor). Related: Rigorously.