adjective
very enthusiastic
Synonyms: ardent, busy, devoted, diligent, eager, fervent, fervid, heartfelt, impassioned, industrious, keen, passionate, perseverant, purposeful, sedulous, sincere, urgent, vehement, warm, wholehearted, zealous
Antonyms: flippant, unconcerned, unenthusiastic, unpassionate, unpurposeful, unthoughtful
adjective
serious; very important
Synonyms: close, constant, determined, firm, fixed, for real, grave, intent, mean business, meaningful, no-fooling, no-nonsense, playing hard ball, resolute, resolved, sedate, sincere, sober, solemn, somber, stable, staid, steady, thoughtful, weighty
Antonyms: flippant, insincere, thoughtless, trivial, unimportant, unserious