Sentence:  The <WSD>custodian</WSD> does such admirable work, deftly wielding a mop to keep our hallways and sidewalks free of buai pekpek left by people who chew betelnuts to be "cool" but don't even bother finding a rubbish bin or spit cup to dispose of the pekpek with. 
Meaning of the word marked with <WSD> tags:  a janitor; a cleaner