Answer: billow

AnswerCrossword Clue
BILLOWSwell
BILLOWSurge or swell
BILLOWPuff up in the wind, as a sail
BILLOWPuff up in the breeze
BILLOWCloud surge
BILLOWSwell out
BILLOWSea swell.
BILLOWSwell, as a cloud
BILLOWPuff out
billowA large undulating mass of something, typically cloud, smoke, or steam
billowto swell (to increase in size or volume)
billowA large sea wave
billowto rise or roll in or like a great wave; surge.