Acting furtively means to behave in a secretive and stealthy manner. Some synonyms for acting furtively are behaving surreptitiously, operating covertly, sneaking, or acting slyly. Another way to say it is to behave in a clandestine manner, meaning to do something secretively and in a concealed way. Sometimes, people will act furtively to hide something they are doing, and they may attempt to operate inconspicuously. Other synonyms for acting furtively might include hiding, lying low, or keeping a low profile. Whatever the situation, it's essential to choose the right synonym to convey the intended meaning accurately.