Here are examples of the word/phrase "fighter" used in a sentence and paraphrased in a sentence...
My opponent was a formidable fighter.
My opponent was a formiddable combatant.
He did not give up because he's a true fighter.
He did not give up because he's a true warrior.
A determined and passionate fighter is destined to go far.
A determined and passionate warrior is destined to go far.
Other Examples...