The word cooperation is unhyphenated, though some also spell it as co-operation.
(Canada, US) Of people, belonging to a single ethnicity or nationality.
For Pennsylvania yields to no State in the courage and virility of her sons—plain, unhyphenated Americans, not yet pushed by invaders off the soil; loyal men, whose fathers gave their blood like water for the Union.
First of all, and probably greatest of all in view of most present-day writers, they were "unhyphenated!" This is indeed wonderful! And again, most wonderful! Unhyphenated! So interesting a fact as this, and one so eminently desirable, invites most critical investigation, for the very breath of suggestion insinuates at once that "hyphenism" and "Americanism" are by the very nature of things contradictory, and that "hyphenism" must needs be on a par with, if not exactly the same as, treason. We are therefore very much interested in the new fact that Pennsylvania's glory lies in the giving of "unhyphenated" Americans to the new nation born of the travails of the Revolution.
Some believe it is an expression of Hebrew-Americanism, others think it is an expressio of Negro-Americanism, still other's think it is pure American, unhyphenated.
2007, Herb Duerr, The Unhyphenated Canuck: Reflections and Confessions of an Opinionated Immigrant, iUniverse.com
The Unhyphenated Canuck: Reflections and Confessions of an Opinionated Immigrant (title)