What does the cryptic crossword clue "It's scary to carry on endlessly being knocked back (3)" mean?

The definition is "It’s scary". The wordplay uses a reversal. KEE (reversal="KEE") = EEK; definition: "It's scary" The answer is EEK.

It's scary to carry on endlessly being knocked back (3)

Times Cryptic #28999 | 27 Across | 2024-08-19 flower