To support or maintain at a high level.
To maintain or enhance enthusiasm or confidence; to lift the spirits of.
To keep afloat or aloft; used with up.
To mark with a buoy.
A life-buoy; a life preserver.
A float moored in water to mark a location, warn of danger, indicate a navigational channel or for other purposes
To be adequate or helpful for a significant amount of time.
To achieve considerable success.