'intentionally-fired' is a compound formed in modern English from 'intentionally' + 'fired'. 'Intentionally' ultimately comes from Latin 'intentio'/'intentionalis' via Old French and Middle English, meaning 'with intention'. 'Fire' originates from Old English 'fyr' and Proto-Germanic *fūr, meaning 'fire; to set on fire'.

'intentionally' developed from Latin 'intentio' → Old French 'intencion' → Middle English 'intencioun' and later 'intentional' with the adverbial -ly. 'Fire' changed from Old English 'fyr' to Middle English 'fir(e)' and the verb sense 'to fire' (to discharge or to dismiss) developed in later Middle English to Early Modern English; these elements combined productively in modern English to form compound phrases like 'intentionally fired'.

Originally, 'fire' primarily referred to combustion ('to set on fire'); over time it gained extended senses including 'to discharge a weapon' and figuratively 'to dismiss from a job'. Combined with 'intentionally', the compound now specifically denotes that an act of firing (shooting or dismissal) was done deliberately.