'assassination' originates from Arabic, specifically the word 'ḥashshāshīn', where 'ḥashshīsh' meant 'hashish' (the name was applied to a sect allegedly associated with hashish use).

'assassin' entered European languages via Old French and Italian from Arabic 'ḥashshāshīn'; from the verb forms 'assassiner'/'assassinare' the noun 'assassination' was formed in early modern English with the suffix '-ation'.

Initially related to the name of a sect (the 'Ḥashshāshīn'), it later came to mean the act of murdering a prominent person and then specifically politically or ideologically motivated killing.