To engage in aimless or wasteful activity; to tinker or fiddle around without accomplishing anything.
Likely from Scots or northern English dialect, possibly related to 'fuss' or from onomatopoeia suggesting ineffectual movement, combined with '-er'.
Scots English has gifted standard English dozens of vivid words that capture specific experiences—'fooster' perfectly describes the frustration of wasting time on something pointless, which is why regional dialects often preserve emotional truths that standard language misses.
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