infield hit
Baseball term for a hit that does not leave the infield, allowing the batter to reach first base safely.
He got on base with an infield hit.
内野安打 is a synonym for 内安打, though 内安打 is more common in modern usage.
Compound of 内 (nai, 'inside') + 安打 (anda, 'safe hit'), referring to a hit that stays within the infield.