What is the meaning of For-?

Forth: prefixed to verbs to indicate a direction of 'away', 'off', 'forth'.

Exhausting: prefixed to verbs with the sense of wearing or exhausting one's self.

Destructively: prefixed to verbs with the sense of destruction or pain.

Wrongly: prefixed to verbs with the sense of wrongly, amorally.

Neglectfully: prefixed to verbs with the sense of abstaining from or neglecting.

Very: intensifying adjectives.

Making: prefixed to verbs to indicate the subject takes the character of the verb.

Excessively: prefixed to verbs with the sense of doing so in excessive or overwhelm.

Excluding: prefixed to verbs to give the sense of prohibition or exclusion.

Intensively

Thoroughly: prefixed to verbs with the sense of thoroughly, all over.

Alternative form of fore-.

Outside, out.

Makes verbs from adjectives meaning "to cause to be [adjective]".

Denotes initial or preparatory action; pre-.

Movement to a distance.

Disappearance or annihilation.

prefix used to express error, exclusion, or inadequacy

previous, before, first, pre-

extremely

negative meaning

over, superior, super-

outer, external

great, extreme

Forms verbs meaning "far", "out" or with an intensive sense; for-.

Forms verbs denoting a failure or error; for-.

Forms nouns with varying sense.

previous, before, first, pre-

extremely

negative meaning

wrongly, away from, astray, abstention, prohibition, perversion, destruction

used to create intensified adjectives and verbs from other adjectives and verbs, with the sense of completely or fully; compare Modern English use of up

very

over-

Alternative form of far-

Source: wiktionary.org