luff
Concise Oxford English Dictionary © 2008 Oxford University Press:
luff /lʌf/ chiefly Sailing
▶noun the edge of a fore-and-aft sail next to the mast or stay. ▶verb steer (a yacht) nearer the wind.
■ obstruct (an opponent in yacht racing) by sailing closer to the wind.
– origin ME: from OFr. lof, prob. from Low Ger.
'luff' also found in these Oxford entries:

