Under-irnan

According to the Old English Dictionary:

under-irnan

to under-run, run beneath :-- Hé underyrnþ ealle ða twelf tácna, Lchdm. iii. 248, 1. Ðonne seó sunne hí hæfð ealle underurnen, 246, 10. ¶ As a gloss of succurrere :-- Underiorn succurre, Rtl. 43, 17. under-irnan