Zángano is Spanish for drone (as in the asexual, genetically identical organisms that form the majority of a bee colony). In some regional dailects, it is used as a term of contempt for a useless, lazy person; in this context the use may be extended to that of a general, mild slur in the sense of schmuck or dumbass.
Slang usaage:
"Sara es como mi hermana, pero su novio es un zángano."
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"Sara's like a sister to me, but her boyfriend's a zángano."
...
"Zángano!" (contemptiously spoken to someone you find worthless)
A trip to a grocery store, convenience store, or gas station for the sole purpose of buying an excessive amount of junk food and sugary drinks, usually with friends. A chud run often happens late at night and ends with everyone involved hating themselves afterwards.