English

aginner

From agin (“against”) + -er.

Formed from agin ‘against’ + -er

Proto-Germanic *in gagin

…

Old English onġēan ‘towards, against, opposite to, contrary to,…’

Middle English agayn ‘again’

Scots again ‘against’

Scots agin

English agin

Today it means

noun An oppositional person, especially one opposed to government actions and projects.

Language periods are conventional ranges, not dates for this word.