The phrase "disastrous season" refers to a period of time, usually in sports or other activities, where things go very badly or result in a terrible outcome. Full definition
Early cup exits and a bottom half finish would be a relatively disastrous season. (westhamway.net)
It has been a fairly disastrous season for Arsenal overall, with Arsene Wenger's future being called into question once again as the club continue to go backwards. (caughtoffside.com)
after several disastrous seasons in F1 and pretty much wasting a lot of time and money on the WEC. (evo.co.uk)