A person who takes money from other people by lying to them. Note that the line you were given describes the verb 'swindle'; the word here is the person who does it. What separates a swindler from a plain thief is the method: nothing is grabbed. The victim hands the money over willingly, because they have been convinced — of a business that does not exist, an investment that will never pay, a fee they do not really owe. That is why swindlers are often charming and well-dressed in stories; charm is the tool. The word carries clear disgust, but it also sounds a little old-fashioned and literary now, the word of novels and newspaper headlines from an earlier time. Today's English speakers are more likely to say con artist, scammer, or fraudster, and in Taiwan the phone and LINE scams you hear about daily would be described with 'scammer'. Still, everyone knows 'swindler', and it remains the natural word when you want a formal or slightly dramatic tone.