Lewis & Short

sŭbabsurdē, adv., v. subabsurdus fin.

sŭb-absurdus, a, um, adj., somewhat or rather absurd (Ciceronian): sunt illa subabsurda, Cic. de Or. 2, 67, 274: subabsurda dicere, id. ib. 2, 71, 289: tempus discessūs, id. Att. 16, 3, 4: incompositus, reconditus et, quo Cicero utitur, subabsurdus, Quint. 1, 5, 65; cf. id. 6, 3, 23; 6, 3, 99.
Adv.: sŭbabsurdē, somewhat absurdly: aliquid subabsurde dicere, Cic. de Or. 2, 68, 275.