2.
A person who likes, knows about, and appreciates a usually fervently pursued interest or activity.
OCADNIOFIA
3.
An ardent admirer or enthusiast (as of a celebrity or a pursuit)
NFA
4.
A person exhibiting a compulsive, chronic, physiological or psychological need for a habit-forming substance, behavior, or activity
DATCDI
5.
An enthusiast or expert especially in a technological field or activity
EGKE
6.
A passionate person about an specific topic (film, aviation)
FFUB
7.
A person who engages in a pursuit, study, science, or sport as a pastime rather than as a profession
EARUATM
8.
Someone who engages in an activity or interest regularly for pleasure rather than for financial gain or professional reasons.
IBSYHOTB
9.
Sometimes used informally to refer to individuals who are particularly passionate about the technical and mechanical aspects of aviation.
REAELERLD-POHP
10.
An engineer who specializes in the design, development, testing and maintenance of aircraft, spacecraft and equipment used in aerospace exploration.