Þrýþ-swíþ

According to the Old English Dictionary:

þrýþ-swíþ

adj. Exceedingly powerful :-- Mǽre þeóden unblíðe sæt, þolode ðrýðswýð, þegnsorge dreáh the great prince sat cheerless, he, mighty, suffered, grief for his thanes' loss he endured, Beo. Th. 262; B. 131. Þrýðswýð beheóld, mǽg Higeláces, hú se mánscaða gefaran wolde, 1477 ; B. 736. [Cf. the proper names Æþel-swíþ, Beorht-swíþ.] þryþ-swiþ