Forego - forgo
The two verbs 'to forego' and 'to forgo' are easily confused, for obvious reasons, not least because etymologically they are the same word. (They are both derived from the irregular verb 'to go', with varied prefixes: see for - fore.) However, usage has developed which has given them different senses. You are advised to be careful to use them in the following way in academic writing. Burchfield's Fowler observes, clarifying the writing of Fowler's first edition: "The variants forego (for forgo) and forgo (for forego) are occasionally found but are ill-advised," . So this is an error that has existed since before 1926. Do not make it - if you can help it.
It may help to clarify your mind if you distinguish the pronunciations, although not every good native speaker of English does so. Use a clearer '-oh-' vowel IPA: /əʊ/ in the first syllable of forego, and give the syllables more equal stress, or even, for emphasis, stress the first syllable - 'FOR - GO' (IPA: /fɔːr gəʊ/ or IPA: /ˈfɔːr gəʊ/). Stress forgo (without the '-e-') differently: place the emphasis clearly on the second syllable - 'fer-GO' IPA: /fər ˈgəʊ/.
- forgo is the commoner. It means 'to go without', 'to abstain', 'to deny oneself'. Its forms are - naturally - forgo ~ forwent ~ forgone. (OED, which records all usages impartially, defines this under the heading forgo, forego, v..)
- forego (this is a meaning separately classified in OED under forego, v., although it gives the same etymology for both) means 'to go be fore', either in position or in time. In its most common occurrences, the -ing participle foregoing and the -ed participle foregone, it is absolutely regular to write with the '-e-', and it would be a mistake to write
forgoingand forgone. (You are likely to see 'foregoing' in such phrases as "The foregoing paragraphs were intended to show that...", "The foregoing has been disproved by Professor X in his book ..." and "The foregoing argument is much disputed." Foregone turns up most in such phrases as 'a foregone conclusion', where it means 'inevitable'. (OED, at foregone, p[articipial] a[djective], defines the phrase thus: "foregone conclusion: a Shaksperian [sic] phrase ... Now used for: A decision or opinion already formed before the case is argued or the full evidence known (hence foregone intention, opinion, etc.); also, a result or upshot that might have been foreseen as inevitable." (OED).) See also Foregoing - forgoing.