lobtail

[lob-teyl]

verb (used without object)

(of a whale) to slap the flukes against the surface of the water.

Origin of lobtail

1865–70 (as gerund); apparently lob¹ in sense “to move heavily” + tail¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018