It may would be tough.
The placement of "would" after "may" when we refer it for future, is it appropriate?
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Sign up to join this communityNo, you should not use both together.
It may be tough.
Or
It would be tough.
"May" indicates that you're less sure of the outcome - it's possible it will be tough, but who knows.
"Would" indicates a greater certainty that it will be tough.
SHORT ANSWER:
This is not grammatical, because may must be followed by a verb in the infinitive form (only an adverbial may intervene), but would is not infinitive—in fact, would does not have an infinitive form.
LONGER ANSWER:
English verbs have only a small number of different forms. Most verbs have three finite forms—the forms which are marked for tense and, in some cases, for person and number.
Past (sometimes called the -ed form, because in most verbs it ends in -(e)d; but in irregular verbs it often ends in -t or has a vowel change): talked, sang, had, were
BE has some extra finite forms: 1st singular present am and 1st/3d past was.
Every complete clause has one, and only one, verb in finite form. When the verb built with one or more auxiliary verbs before the main verb, as in a passive or progressive or perfect construction, the finite verb is always the first auxiliary in the chain. The rest of the verbs in the chain must take one of three non-finite forms (which form is determined by the preceding auxiliary). These non-finite forms have no tense, person or number; all of which are inferred from the context:
Thus, almost all English verbs have between four and eight different forms to play six different roles, three finite and three non-finite. But there are a few special verbs which linguists call defective, because they have only one or two forms and they play only three of the usual roles.
These are the modal verbs: can/could, may/might, must, shall/should will/would. These verbs have only two forms, both finite: a present form (without a distinct 3d person singular) and a past form. They have no non-finite forms: no present participle, no past participle, and no infinitive.
Consequently, in Standard English these verbs can only stand at the head of verb chain, as the single finite verb in the chain, never in a second or later position. And there can only be one of them—they cannot be chained or ‘stacked’.
These rules are not always observed in dialect. As wordsmythe notes, you might encounter constructions like I might could do that or He mighta shoulda told you in speech or in written dialog. But those are not acceptable in Standard English, either written or spoken, unless they are used ironically.