I almost mistook 'humbug' for 'hamburger'.

I almost mistook 'humbug' for hamburger'. I have no idea what humbug means. Since bug is a annoying insect, so hum+bug=a annoying person.  It is my wild guess.
I came across the word 'swindler' in one of the novels I read before. I have a vague memory of it. 'Swindler' means 'cheater'. Am I right?