A loan army is a squad of young or fringe players a club signs and then lends out in bulk, so they develop and get seen somewhere else. FIFA now limits the practice, capping how many players a club may loan out and take in across borders in a season.
The model made sense on its own terms. A wealthy club could sign promising players it had no immediate place for, spread them across smaller clubs at home and abroad, and sell the ones who developed at a profit while keeping the ones who became good enough for its own team.
The objections were that it hoarded talent and distorted competition. Dozens of players controlled by one club and scattered across rival leagues gave that club influence far beyond its own squad, and left players stuck in a cycle of temporary moves.
FIFA responded with a cap on international loans, phased in across several seasons and reaching a single-figure limit on players loaned out and taken in per season, with carve-outs for younger players and those the club trained itself. Domestic loans within the same association are governed separately.