nonconference
adjective
non·con·fer·ence ˌnän-ˈkän-f(ə-)rən(t)s 
-fərn(t)s
: not of, relating to, or occurring within a conference
especially : of, relating to, or involving play between athletic teams that do not belong to the same conference (as in college football or basketball)
nonconference games/opponents
a nonconference victory
… facing a brutal nonconference schedule that included away games against Texas, North Carolina, Kansas, Arizona and Kentucky … 
Tim Crothers
Tim Crothers 
Example Sentences
Recent Examples on the Web The Blue Devils simply don’t lose nonconference home games — this was their 148th consecutive victory against a non-ACC opponent at Cameron — but there were plenty of teachable moments for Krzyzewski’s young team. Joedy Mccreary, The Denver Post, 8 Nov. 2019 The Cardinal have won their past 21 nonconference home games; their last such loss was a 21-14 decision to Notre Dame in 2007. Steve Kroner, SFChronicle.com, 30 Aug. 2019
Joedy Mccreary, The Denver Post, 8 Nov. 2019 The Cardinal have won their past 21 nonconference home games; their last such loss was a 21-14 decision to Notre Dame in 2007. Steve Kroner, SFChronicle.com, 30 Aug. 2019 Word History
First Known Use
1901, in the meaning defined above