rigorous
[adjective]
Synonyms: strict, demanding, exacting, hard, harsh, inflexible, severe, stern, stringent, tough

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Antonyms: mild
Contrasted words: easy, effortless, facile, light, smooth, bland, faint, lenient
Related Words: inflexible, stiff, ascetic, burdensome, exacting, onerous, oppressive, drastic

[TahlilGaran] English Synonym Dictionary ▲

rig‧or‧ous /ˈrɪɡərəs/ adjective

1. careful, thorough, and exact:
a rigorous analysis of defence needs
the rigorous standards required by the college

2. very severe or strict:
rigorous army training
—rigorously adverb

[TahlilGaran] Dictionary of Contemporary English ▲