Entry 1 sense Webster, 1913 Overlash · O·ver·lash · IPA /əʊvə(ɹ)ˈlæʃ/ 01 v. i. To drive on rashly; to go to excess; hence, to exaggerate; to boast. 1. To drive on rashly; to go to excess; hence, to exaggerate; to boast.[Obs.]