'anti-choicer' is formed from the prefix 'anti-' and the noun 'choice' with the agentive suffix '-er'. 'anti-' originates from Greek, specifically the word 'anti', where 'anti-' meant 'against'. 'choice' originates from Old English, specifically the word 'ceosan', where 'ceosan' meant 'to choose'. The suffix '-er' originates from Old English where it formed agent nouns.

'choice' changed from Old English 'ceosan' to Middle English forms such as 'choisen' and then to modern English 'choice'. The modern compound 'anti-choice' (opposed to 'choice') arose in contemporary political discourse, and 'anti-choicer' developed as an agent noun referring to a person holding that position.

Initially, the elements meant 'against' + 'to choose' + agent (a person). Over time, the compound came to refer specifically to people opposed to the legal or political idea of reproductive choice, especially opponents of abortion rights.