'collarless' originates from English, formed by the combination of the noun 'collar' and the suffix '-less' (meaning 'without').

'collarless' was created in Modern English by attaching the Old English/Norman-derived noun 'collar' to the Germanic/Old English suffix '-less'; the noun 'collar' itself comes from Middle English 'coler'/'coller', from Old French 'coler'/'cole', and ultimately from Latin 'collare' (related to 'collum' meaning 'neck').

The term initially and historically meant 'without a collar' and has retained this literal meaning in modern usage.