Answer:

wave

Answer	Crossword Clue
WAVE	Ballpark antic
WAVE	High sign
WAVE	Stadium audience participation

WAVE	Undulation
WAVE	Make a motion
WAVE	Waikiki ride
WAVE	Group action
WAVE	It's sometimes permanent
WAVE	Surfer's surface
WAVE	Gesticulate
WAVE	Type of hairdo

WAVE	Loose curl
WAVE	Fenway crowd action
WAVE	Swell
WAVE	Greet, in a way
WAVE	Gestured greeting
WAVE	Hi sign
WAVE	Breaker on the shore
WAVE	Hi from a float

WAVE	Breaker at the shore
WAVE	-
WAVE	It may be new or permanent
WAVE	Oceanside sight
WAVE	Surfer's ride
WAVE	Surfing sine qua non
WAVE	Breaker
WAVE	Swell sight?

WAVE	This goes around an arena
WAVE	Surfer's need
WAVE	Greet from a distance
WAVE	Greet from across the street, perhaps
WAVE	Undulation in the stands
WAVE	Signal "Hi!" or "Bye!"
WAVE	Ocean swell
WAVE	Surfing need

WAVE	Surfer's challenge
WAVE	Surfer's joy
WAVE	Wordless greeting
WAVE	Activity at a football stadium
WAVE	Say "Hi" with a hand