Developmental Dysplasia of the Hip (DDH): This condition is characterized by an abnormal formation of the hip joint, where the ball-and-socket do not fit properly. An audible hip click in an infant is a classic sign that may indicate DDH, making it the most likely diagnosis in this scenario.

Transient Hip Instability: Some infants may have transient hip instability that can cause a clicking sound, which often resolves on its own as the child grows.
Hip Subluxation: A condition where the hip joint is partially dislocated, which could also cause an audible click.

Slipped Capital Femoral Epiphysis (SCFE): Although more common in older children and adolescents, SCFE is a serious condition where the ball at the upper end of the femur slips out of place. Early detection is crucial, and an audible hip click could be an initial sign in younger patients.
Septic Arthritis of the Hip: An infection within the hip joint, which is a medical emergency requiring prompt treatment. While less likely to present solely with an audible click, it's a critical diagnosis not to miss due to its potential for severe consequences.

Synovial Chondromatosis: A rare condition where cartilage grows in the synovium of the joint, potentially causing clicking or snapping sounds.
Intra-articular Loose Bodies: Small pieces of bone or cartilage within the joint can cause mechanical symptoms, including clicking sounds, though this is exceedingly rare in infants.