Feat, n.
Etymology: [OE. fet, OF. fet, fait, F. fait, factum, fr. L. facere, factum, to make or do. Cf. Fact, Feasible, Do.]
1. An act; a deed; an exploit. The warlike feats I have done. Shak.
2. A striking act of strength, skill, or cunning; a trick; as, feats of horsemanship, or of dexterity.
2 other Webster entries under this spelling
Feat, v. t.
To form; to fashion. [Obs.] To the more mature, A glass that feated them. Shak.
Feat, a. [Compar. Feater; superl. Featest.]
Dexterous in movements or service; skillful; neat; nice; pretty. [Archaic] Never master had a page . . . so feat. Shak. And look how well my garments sit upon me --Much feater than before. Shak.
Shades of meaning
Fernald has no entry of its own for feat; he lists it under act.
Where he writes about it:
As between act and deed, deed is commonly used of great, notable, and impressive acts, as are achievement, exploit, and feat. — from act
A feat exhibits strength, skill, personal power, whether mental or physical, especially the latter; as, a feat of arms, a feat of memory. — from act