'attitudinize' originates from the noun 'attitude' plus the verb-forming suffix '-ize'. The suffix '-ize' derives ultimately from Greek '-izein' (via Latin and French), used to form verbs meaning 'to make or to behave in the way of'.

'attitude' entered English from French 'attitude' (17th century), itself from Italian 'attitudine', which traces back to Latin 'aptitudo' ('fitness' or 'suitability'). The productive English suffix '-ize' was adopted from French/Latin forms and Greek verbalizing suffixes, producing 'attitudinize' as 'to make into/assume an attitude'.

Initially related to physical position or posture ('attitude' as 'position'), the sense shifted to include manner or mental/behavioral stance; 'attitudinize' came to mean 'to assume a (often affected) manner or pose'.