Vaunt, v. i. [imp. & p. p. Vaunted; p. pr. & vb. n. Vaunting.] — Webster enters it under “vaunt”
Etymology: [F. vanter, LL. vanitare, fr. L. vanus vain. See Vain.]
To boast; to make a vain display of one's own worth, attainments, decorations, or the like; to talk ostentatiously; to brag. Pride, which prompts a man to vaunt and overvalue what he is, does incline him to disvalue what he has. Gov. of Tongue.
4 other Webster entries under this spelling
Vaunt, v. t.
To boast of; to make a vain display of; to display with ostentation. Charity vaunteth not itself, is not puffed up. 1 Cor. xiii. 4. My vanquisher, spoiled of his vaunted spoil. Milton.
Vaunt, n.
A vain display of what one is, or has, or has done; ostentation from vanity; a boast; a brag. The spirits beneath, whom I seduced With other promises and other vaunts. Milton.
Vaunt, n.
The first part. [Obs.] Shak.
Vaunt, v. t.
To put forward; to display. [Obs.] "Vaunted spear." Spenser. And what so else his person most may vaunt. Spenser.
Shades of meaning
Fernald has no entry of its own for vaunting; he lists it under ostentation.
He lists it without comment; the entries above explain its neighbors.