Sentence:  This means an added burden to innumerable postmen , who already are <WSD>complaining</WSD> of heavy loads and low pay , and it presumably means an increased postal deficit , but , our correspondent writes , think of the additional junk mail each citizen will now be privileged to receive on a regular basis . 
Meaning of the word marked with <WSD> tags:  express complaints, discontent, displeasure, or unhappiness