veteran

old-time skilled trained

adept expert old pro steady versed vet wise

battle-scarred been around disciplined exercised from way back hardened inured knows one's stuff long-serving long-time not born yesterday of the old school practical practiced proficient sophisticated up to speed weathered wise to ways worldly

unskilled

amateur green inexperienced

expert pro vet

GI old-timer sourdough trouper war-horse

old guard old hand old pro old salt old soldier shellback

rookie