Chugger (someone who is paid to stop people in the street and persuade them to give money regularly to a Charity - persona a la que pagan para que aborde a la gente en la calle, tratando de convencerlos para que den dinero de forma regular a una causa benéfica) is an example of blend, a type of word formation in which two words are combined to form a new word that incorporates their meanings, for example motel from motor and hotel. Chugger is made up of charity + mugger (caridad + 'atracador' en lugar público).
Another name given to blends is portmanteau words, a term invented by Lewis Carroll (1831-1898), who produced some of them in his novel Alice's Adventures in Wonderland, for example to chortle (reír con ganas) = to chuckle + snort. Here are some more examples of blends:
brunch = breakfast + lunch (desayuno-almuerzo)
cheeseburger = cheese + hamburger (hamburguesa con queso)
chunnel =channel + tunnel (tunel bajo el Canal de
la Mancha, Eurotunel entre
Gran Bretaña y el continente europeo)
Eurovision = European + television (Eurovisión)
paratroops = parachute + troops (paracaidistas).