Sentence:  The First World War may have brought, as Dos Passos maintained, an end to "the bully amateur's world," but <WSD>amateur hour</WSD> was already closing down as American soldiers struggled up San Juan Hill. Three books written between 1897 and 1899 are flashes that streaked the sky at the moment "the boy culture" of volunteers was displaced (and absorbed) by the "dirtywork" of regulars committed to the culture of management. 
Meaning of the word marked with <WSD> tags:  A situation or activity in which the participants show a lack of skill, sound judgment, or professionalism.