(n.) The quality or state of being keen.

absolute zero acerbity acidity acidness acidulousness acridity acrimony acuity acumen acumination acuteness adroitness agility alacrity alertness algidity animation anxiety anxiousness appetite aptitude aptness asperity astringency astuteness attention attentiveness avidity avidness bite bitingness bitterness bleakness braininess breathless impatience brightness brilliance briskness causticity causticness cheerful readiness chill chilliness clear thinking cleverness cold coldness cool coolness coolth corrosiveness crispness cryogenics cryology cuttingness decrease in temperature dexterity discernment discrimination eagerness edge elan esprit facetiousness fierceness flair forwardness freezing point freshness frigidity frostiness funniness gelidity genius giftedness gifts grip gust gusto harshness humorousness iciness impatience incisiveness inclemency intense cold jocoseness jocularity joking joshing keen desire keen-wittedness life liveliness low temperature mental alertness mercurial mind mordacity mordancy mucronation native cleverness nimble mind nimble-wittedness nimbleness nip nippiness nous penetration percipience perspicacity piercingness piquancy pleasantry poignancy point pointedness prickliness promptitude promptness punctuality pungency quick parts quick thinking quick wit quick-wittedness quickness rawness readiness ready wit rigor roughness saltiness savvy severity sharp air sharp-wittedness sharpness shrewdness sleeplessness smartness smarts sourness spinosity spirit sprightly wit stabbingness sting stridency stringency talent tartness teeth thorniness trenchancy vehemence verve violence virulence vitality vivacity wakefulness wit wittiness zest zestfulness