outsize adjective 2noun 1verb 1forms 3 adjective2 •Of an unusually large size . •Unintuitively or unexpectedly large.Small changes in initial conditions can have an outsize effect on the course of events. noun1 •An unusually large garment size. verb1 •To exceed in size.Mega-ship to outsize seas' reigning Queen. — 2005 formsoutsized · outsizing · outsizes