empty the tank

empty suit

An ineffective or incompetent person in a place of authority.

empty the clip

To compete with great vigor, especially by making numerous scoring attempts.

empty words

Any type of talk with little meaning; a message that seems to contain meaningful content but is actually vapid.

run on empty

To be losing enthusiasm or willingness; to lack motivation.

think tank

A group of people who collectively perform research and develop reports and recommendations on topics relating to strategic planning or public policy, and which is usually funded by corporate, government, or special interests.