Sentence:  ‘Don't you see what you would be? You'd be a <WSD>knobstick</WSD>. You'd be taking less wages than the other labourers—all for the sake of another man's children. Think how you'd abuse any poor fellow who was willing to take what he could get to keep his own children. You and your Union would soon be down upon him ...' 
Meaning of the word marked with <WSD> tags:  One who refuses to join, or withdraws from, a trade union.