'constitutionalism' originates from the adjective 'constitutional' combined with the suffix '-ism'. 'Constitutional' ultimately comes from Latin 'constitutio' (via Medieval Latin and Old French), where the root 'constituere' meant 'to set up' or 'to establish', and the suffix '-ism' derives from Greek '-ismos' (via Latin/French) meaning 'practice, system, or ideology'.

'constitutionalism' developed in English by adding the noun-forming suffix '-ism' to 'constitutional' (which itself came from Middle English/Old French 'constitution' and Latin 'constitutio'), resulting in the modern English noun 'constitutionalism' referring to the system or doctrine centered on a constitution.

Initially the root 'constitutio' referred to an 'establishment' or 'arrangement'; over time the meaning shifted through 'constitution' (a settled law or system) to the modern sense of 'constitutionalism' as the political doctrine that a constitution limits government power.