'antijam' originates from Modern English, formed by the Greek prefix 'anti-' (from Greek 'antí') meaning 'against' combined with the English word 'jam' (originally imitative/uncertain origin) meaning 'to block or squeeze'.

'antijam' developed from the hyphenated technical compound 'anti-jam' used in late 20th-century engineering and communications writing; in some usages the hyphen was later dropped to form the closed compound 'antijam'.

Initially the compound literally meant 'against jam' (physically preventing a blockage); over time its use broadened to cover preventing radio or electronic interference, so its current sense is 'preventing jamming or interference'.