'unconditionalism' originates from English formation: the adjective 'unconditional' + the suffix '-ism' (from Greek/Latin via English) where 'un-' is a negative prefix meaning 'not', 'conditional' is from Latin 'condicio/conditio' meaning 'a stipulation or agreement', and '-ism' denotes a practice, doctrine, or system.

'unconditionalism' was formed in modern English by combining 'unconditional' (itself built from 'un-' + 'conditional') with the suffix '-ism'. 'Conditional' ultimately comes from Latin 'condicio' > Old French/Latin-derived Middle English 'condition'; the productive English suffix '-ism' was added to create a noun meaning 'doctrine or practice of being unconditional.'

Originally the elements meant 'not' + 'a stipulation/agreement' + 'doctrine/practice'; over time the compound came to mean specifically 'the doctrine, quality, or practice of lacking conditions' and is used in contexts such as policy, theology, ethics, and personal relationships.