In verbs the prefix denotes (a) intensive or completive action or process, or (b) action that miscarries, turns out for the worse, results in failure, or produces adverse or opposite results. In many verbs the prefix exhibits both meanings, and the verbs frequently have secondary and figurative meanings or are synonymous with the simplex. Some of these verbs were inherited from OE, many others were formed during the ME period. Examples: (a) for-bannen banish; -bēren bear, endure, refrain, avoid; -bīen redeem, bribe; -bīnden tie up; -blẹ̄den bleed hard or to death; -brēken break up, shatter; -drēden fear greatly; -drenchen intoxicate, drown;-drīen dry up, wither; -hēlen, -hīden conceal; -lēten forsake, give up, neglect, lose; -wẹ̄pen weep hard or long; -werpen cast out, banish, reject, renounce; -wǒunden wound, injure; -yēven forgive, give up, bestow, grant; (b) for-breiden corrupt, pervert; -dẹ̄men condemn, convict; -dọ̄n ruin, destroy, condemn, frustrate, prevent, abrogate, violate; -fāren go astray, perish, ruin; -houen despise, scorn; -lēden mislead; -līen fornicate, ravish, commit adultery; -wǒrthen degenerate, spoil, perish; -yēten forget, neglect, omit. This prefix occurs also in the many nouns and adjs. formed on such verbs.

Beside the usual ppls. of verbs with prefix for-, ME coined many ppls. that were used only as pred. adjs., such as for-derked dimmed, obscured; -drǒnken given to drunkenness; -fēred terrified; -hǒngred ravenous, starving; -lived decrepit; -wandred exhausted from wandering; -wēred worn out; -wǒndred amazed. Here the prefix has intensive or completive force. Alongside of these ppls., ME had a number of adjs. with prefix for-, thus for-dulle beside for-dulled, for-wẹ̄rī beside for-wērīed; and some that are not paralleled by ppls., as for-cold (1330) very cold, and -cǒuth [OE] infamous, wicked, vile, miserable.

A few OE primary action nouns with prefix for- survive in ME, as for-bō̆d prohibition (cp. for-bẹ̄den prohibit, forbid); for-wīrd perdition, destruction (cp. for-wǒrthen degenerate, perish).

The OE adverb for-wel, in which the prefix is a simple intensifier, survives briefly in ME.