look up any word, like plopping:
 
1.
1. A derogatory term for any species of extraterrestrial that can be killed by an average man with their bare hands; or generally has a very thin / frail physical form. This does not include any advantage the ET has due to technology, mind control, etc.

At least one species, the grey alien, is considered a frailien.
Abductee: "The alien that tried to abduct me was weak, I snapped his neck with a single punch!"
Friend: "Yeah, that things was frail. It was a frailien!"
by Alien Killer August 14, 2011