in the (first) flush of

:  preceding all others in time, order, or importance: such as

:  earliest

:  being the lowest forward gear or speed of a motor vehicle

:  before another in time, space, or importance

:  for the first time

:  in preference to something else :  sooner

:  something that is first: such as

:  the first occurrence or item of a kind

:  the first forward gear or speed of a motor vehicle

:  to fly away suddenly

:  to cause (a bird) to flush

:  to expose or chase from a place of concealment

:  a hand of playing cards all of the same suit

:  a poker hand containing five cards of the same suit but not in sequence — see poker illustration

:  a series of three or more slalom gates set vertically on a slope

:  a sudden flow (as of water)

:  a rinsing or cleansing with or as if with a flush of water

:  a sudden increase or expansion

:  to flow and spread suddenly and freely

:  to glow brightly

:  blush

:  of a ruddy healthy color

:  full of life and vigor :  lusty

:  filled to overflowing

:  in a flush manner

:  squarely

:  to make flush