Very common in 17th century.
1581. Sidney, Apol. Poetrie (Arb.), 46. As the vnimitable Pindar often did.
1622. F. Markham, Bk. War, Ep. Ded. A 3 b. As by his owne vnimitable pen is protested.
1683. Kennett, Erasm. on Folly, 48. As they [sc. bees] give a model of in their unimitable Combs.
1695. J. Edwards, Perfect. Script., Ded. You bore the … insults of the enemy with unimitable bravery.
1773. Johnson, in Shakespeare’s Wks., V. 508 But Falstaff unimitated, unimitable Falstaff, how shall I describe thee?
So † Unimitably adv. Obs.
1622. Peacham, Compl. Gent., x. 91. His sweetnesse and facilitie in a verse, vnimitably excellent.
1670. Walton, Lives, Donne, 80. His fancy was unimitably high, equalled only by his great wit.
