Third-person singular present tense: he, she, or it covers or fills with smoke.
From besmoke plus the -s ending for third-person singular.
Regular verbs in English are so reliable that we barely notice them, but their regularity is actually a relatively recent development. Old English had many more irregular verbs, and we've been slowly regularizing them—besmokes follows a pattern that's now five hundred years standard.
Complete word intelligence in one call. Free tier — 50 lookups/day.