What is the meaning of Migać?

to blink, to flash, to flicker (to appear while being visible only momentarily during fast movement)

to flicker (to shine with intermittent light)

to make small and fast movements

to signal with flickers (to convey information by turning the lights on and off from time to time)

to use sign language, to sign

to coast, to duckshove (to dodge responsibility; to pass something on to another so that they take the blame) [with od (+ genitive)]

Source: wiktionary.org