A buoy is a floating marker that indicates the presence of underwater hazards, channels, or places for tying up boats. When buoy is a verb, it can mean to float like a buoy, literally or figuratively. Winning an award could buoy your spirits as if you are floating with pride.
The verb buoy can mean "boost or increase." There aren't many things that will buoy your confidence as much as repeated compliments on how great your new haircut looks. Imagine seeing water buoy up an enormous swan, or the wind buoy up a kite. A more figurative meaning of buoy is to cheer or lift someone's spirits. One way to remember buoy's unusual spelling is the phrase, "Boats usually opt to steer around a buoy."