Something that creaks; a person or thing that makes creaking sounds, or informally, something that is old and deteriorating.
From 'creak' (verb) plus the agent noun suffix '-er,' which creates a noun meaning 'one that does the action' or 'something that does the action.'
Agent nouns with '-er' are one of English's most productive word-building tools—nearly any verb can become 'verb-er' for the actor, which is why we can instantly understand new words like 'creaker' even if we've never heard them before.
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