adv. (UN-1 11, 5 b. Cf. prec.)
1733. W. Crawford, Infidelity (1836), 217. Some may allege, and not unplausibly, that [etc.].
1795. Burke, Regic. Peace, iv. Wks. IX. 56. Men would reason not unplausibly, that it would be better [etc.].
1820. Coleridge, Lit. Rem. (1839), IV. 138. Others, again, and not unplausibly, contend [etc.].
1862. M. Hopkins, Hawaii, 85. Cooks two ships appeared to them, not unplausibly, islands, the masts being trees.