expert expert /ˈɛkspɝt/

adjective

1. () Having or showing knowledge and skill and aptitude  ( skilful [Canadian, British] , adept , practiced [ N. American] , expert , good , proficient , skillful [ N. American] )
   having or showing knowledge and skill and aptitude
    Adept in handicrafts
   adept in handicrafts
    An adept juggler
   an adept juggler
    An expert job
   an expert job
    A good mechanic
   a good mechanic
    A practiced marksman
   a practiced marksman
    A proficient engineer
   a proficient engineer
    A lesser-known but no less skillful composer
   a lesser-known but no less skillful composer
    The effect was achieved by skillful retouching
   the effect was achieved by skillful retouching
   
2. Of or relating to or requiring special knowledge to be understood  ( expert , technical )
   of or relating to or requiring special knowledge to be understood
    Technical terminology
   technical terminology
    A technical report
   a technical report
    Technical language
   technical language
   

noun

1. () A person with special knowledge or ability who performs skillfully  ( expert )
   a person with special knowledge or ability who performs skillfully
     Dr. Johnson was recognized as an expert in the field of astrophysics.
   Dr. Johnson was recognized as an expert in the field of astrophysics.