Sentence:  I told him about everything I could think of; and what I couldn't think of he did. He asked about six questions during my yarn, but every question had a point to it. At the end he bowed and thanked me once more. As a thanker he was main-truck <WSD>high</WSD>; I never see anybody so polite. 
Meaning of the word marked with <WSD> tags:  Having a specified elevation or height; tall.