thrash vs thrash about

thrash is a noun but thrash about is not a noun.

Word	Noun	Adjective	Verb	Adverb
thrash	Yes	No	Yes	No
thrash about	No	No	Yes	No

As verbs, thrash and thrash about are synonyms defined as:

Other synonyms of thrash include convulse, jactitate, slash, thresh, thresh about, toss.

thrash (noun)	thrash about (noun)
a swimming kick used while treading water

thrash (verb)	thrash about (verb)
give a thrashing to; beat hard	move or stir about violently
beat the seeds out of a grain
beat thoroughly and conclusively in a competition or fight
dance the slam dance
move or stir about violently
beat so fast that (the heart's) output starts dropping until (it) does not manage to pump out blood at all
move data into and out of core rather than performing useful computation