The phrase "inconsistent season" means that throughout a particular period of time, the performance, behavior, or outcome of something or someone has been varied, uncertain, or not steady. Full definition
It brought the curtain down on the most inconsistent season in the young club's six - year history and will inevitably spark speculation about the future of Spanish coach. (espnfc.com.ar)
Good end to a good if a tad inconsistent season for the Dane. (freshspurs.com)
Another player who has been very inconsistent this season. (justarsenal.com)