(eulogistic) A person with a strong determination to resist protracted or severe adversity, especially illness.
A class of fixed-wing aircraft whose primary purpose is that of shooting down other aircraft. Some of these (Fighter-Attack or Attack aircraft) also have a secondary purpose of attacking ground targets.
A boxer or participant in any martial art.
A firefighter
A game with a focus on physical combat.
All clues having "FIGHTER"
for an answer:
You can find a list of possible crossword clues for FIGHTER below.