Sentence:  It now means ominous , as when one speaks of a funny sound in the motor ; disturbing , as when one says that a friend is <WSD>acting</WSD> funny ; and frightening , as when a wife tells the police that it is funny , but her husband has n't been home for two days and nights '' . 
Meaning of the word marked with <WSD> tags:  behave in a certain manner; show a certain behavior; conduct or comport oneself