'fire-thrower' originates from Modern English, specifically the compound of 'fire' and 'thrower', where 'fire' meant 'flame' (from Old English 'fȳr') and 'thrower' is an agent noun formed from the verb 'throw' (Old English roots such as 'þrawian') meaning 'to propel or cast'.

'fire-thrower' developed as a transparent Modern English compound (post-medieval). It follows patterns of English compounding (e.g. 'stone-thrower') and was later analogically associated with terms like 'flame-thrower' (20th century) and specialized in fantasy literature to denote characters who throw fire.

Initially it denoted literally 'one who throws fire' (a person who casts flaming projectiles); over time the term has been applied metaphorically and descriptively to devices that project flame (akin to 'flamethrower') and to fantasy/magical users who hurl fireballs.