Sentence:  It is a very difficult thing to make a good yarn of <WSD>nitty</WSD> [cotton] stock. The nits will stick to the cotton to quite an extent anyway, in spite of all the efforts made to prevent it. A few years ago we had some very <WSD>nitty</WSD> stock and we got the best results by running the beaters so as to give about 40 blows per inch of stock delivered on our plain two bladed beaters. 
Meaning of the word marked with <WSD> tags:  Full of nits.