Is flump a word in the Scrabble Dictionary

Yes, flump is playable

...and is worth 16 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Flump" Definition

noun

A dull heavy sound, as of something dropped on a surface.
A dull heavy sound (as of a fall).

verb-intransitive

To move or fall heavily with a dull sound: flumped onto the sofa.

verb-transitive

To place or drop with a flump.

To place or drop with a flump.
To move or fall suddenly and heavily .