filst

From Old English fylstan (“to aid, support, help, protect”), contraction of Old English fullǣstan (“to help, support”), from ful-, full- (“full-, fully”) + lǣstan (“to follow, help, serve, perform, do, carry out, accomplish, endure, last, continue, furnish, pay, grant”), equivalent to full- +‎ last. Cognate with Old Saxon fullēstian (“to help, aid”), Old High German fulleistjan (“to help, aid”).

filst (third-person singular simple present filsteth, present participle filstende, filstynge, first-/third-person singular past indicative and past participle filsted)

1. (transitive) To help; aid.

• filstnen