'conjunctionless' originates from English, formed from the noun 'conjunction' and the suffix '-less', where 'conjunction' comes from Latin 'coniunctio' meaning 'a joining together' and '-less' meant 'without'.

'conjunction' came into English via Old French and Middle English from Latin 'coniunctio' (from 'coniungere' 'to join together'); the modern English compound 'conjunctionless' was formed in modern English by adding the productivity suffix '-less' to 'conjunction'.

Initially, 'conjunction' meant 'a joining together' (in general and grammatical senses); over time it specialized to mean the grammatical particles that join clauses or words; combined with '-less', the compound now means 'without such joining words' or 'lacking conjunctions'.