These adjectives are comparable when applied to that which has reached maturity or completion. Full-fledged is the most clourful word. Its literal reference is to a bird whose wing feathers are full grown, enabling it to fly. The noun fledgling is applied to a young bird that has just grown enough feathers for flight; and, by extension, it designates a person who is inexperienced or immature. But full-fledged stresses accomplishment, implying that a training or developing period is past and that full, independent status has been attained: a full-fledged teacher as opposed to a teacher trainee; a full-fledged doctor as opposed to a resident; a full-fledged pilot who has finished his flight training and has won his wings.

Seasoned goes beyond full-fledged , suggesting not only qualification but maturity or experience. Applied to timber, it indicates a drying or hardening process whereby the wood is made more suitable for use. Used of persons, it implies the development of expert skills and professional reliability through long practice: a seasoned polo team; a seasoned trouper, able to go on with the show despite laryngitis; a drill sergeant who took raw recruits and turned them into seasoned troops. A seasoned politician is one who has become astute and adroit in practical politics through having weathered many campaigns.

Finished stresses polish and resulting elegance. Finished furniture has a polished surface. An artist with a finished technique has polished his style to an ultimate degree. A finished musician, as contrasted with a merely competent one, has refined his skills and has achieved excellence. Perfected is close to finished but is more emphatic in stressing consummate mastery or faultless excellence: A perfected technique is the mark of a virtuoso.