Answer: expert

AnswerCrossword Clue
EXPERTKnow-nothing's opposite
EXPERTSkilled.
EXPERTSpecialist
EXPERTMan who knows
EXPERTSkilled one
EXPERTAuthority
EXPERTHighly skilled
EXPERTBlack belt, say
EXPERTMasterful
EXPERTPuzzle-solving level
EXPERTAce.
EXPERTOld hand
EXPERTOld pro
EXPERTType of witness
EXPERTBlack belt
EXPERTCrackerjack
EXPERTAficionado
expertto possess specific skills, also EXPERTISE, EXPERTIZE
expertA person who has a comprehensive and authoritative knowledge of or skill in a particular area
EXPERTGo-to guy
EXPERTAce
EXPERTAdept practitioner
EXPERTWhiz
EXPERTKind of witness
EXPERTGuru
EXPERTCrossword puzzle solver with a pen, often
EXPERTSkillful
EXPERTMaster hand
EXPERTConsultant, probably
EXPERTPro
EXPERTPaid witness, perhaps
EXPERTMaven
EXPERTProficient.
EXPERTMaster.
EXPERTAuthority.
EXPERTMaster hand.
EXPERTQuiz contestant.
EXPERTOne in the know.