To make hard or harder; to harden or strengthen something physically or metaphorically.
From en- (prefix) + harden (from hard, from Old English heard). It's a somewhat archaic way to say 'make harder' or 'strengthen.'
While 'harden' is common (like when clay hardens), 'enharden' adds emphasis—it's used in older texts to describe really solidifying or toughening something, whether physical steel or a person's resolve.
Complete word intelligence in one call. Free tier — 50 lookups/day.