Sentence:  The professed mission of this disaffiliated generation is to find a new way of life which they can express in poetry and fiction , but what they produce <WSD>is</WSD> unfortunately disordered , nourished solely on the hysteria of negation . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)