Region: US | Usage example: He meant well but wasn't the sharpest tool in the shed.

Not the sharpest tool in the shed

Meaning

Not very intelligent or quick-witted.

Used with mild humorous criticism.

Origin notes can vary by region and source; this page gives the commonly reported explanation and usage context.

Toolbox metaphor that equates dull tools with dull minds.

20th-century American humor used the phrase.