To cover, hide, or enclose something with or as if with curtains.
From en- (cause to be) + curtain, meaning to surround or conceal with fabric or a curtain-like barrier, archaic in modern usage.
Fog encurtains a landscape, or theatrical lighting might encurtain a stage—it's a dramatic way to describe being hidden from view by something draped or veiling.
Complete word intelligence in one call. Free tier — 50 lookups/day.