from Wiktionary, Creative Commons Attribution/Share-Alike License.
superlativeform of feat: most feat.
Sorry, no etymologies found.
As for me, get me my bonnet, Jen -- my best Sunday leghorn with the puce _chenille_ in it -- I must look my featest going to a great house to pay my respects.
And, wherever she got her training, you'll find she's the featest-footed among us. "