Bump on a log
Meaning
Someone inert and unresponsive.
Usage
Used to describe passive observers.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Imagery of a log doing nothing.
Common in American speech by the early 1900s.