Rapid Pulsation in the Heart, Vibration
This page is the CodyCross answer for the clue below from Fauna and Flora, Group 171, Puzzle 5 (Bilateral Symmetry).
Question is: Rapid Pulsation in the Heart, Vibration
and the answer is: FLUTTER
Word Meaning:
FLUTTER — (intransitive) To flap or wave quickly but irregularly.
Definitions from Wiktionary.