What does the cryptic crossword clue "Shake beaker, at this? (3,5)" mean?

The wordplay uses an anagram. anagram of BEAKERAT ("beaker, at") [anagram: "Shake"] = TEABREAK The answer is TEABREAK.

Shake beaker, at this? (3,5)

Guardian Cryptic #29363 | 26 Across | 2024-04-22 flower