Junkie is a noun. It refers to (1) someone who is addicted to narcotics, and (2) one who has an insatiable interest in something. In reference to drug addicts, it’s disparaging and might be considered insensitive. Junky is an adjective. It means (1) worthy of being discarded, and (2) meaningless or unbelievable. Some dictionaries list junky as an alternative spelling of junkie in the sense synonymous with addict, but the words are usually kept separate in edited writing.
Isn’t this exactly like drip-feeding heroin to a junkie? [Daily Mail]
At 37, Lisa Sharp is comfortable calling herself a video-game junkie. [CNN]
At the base of the mountain a mix of glamorous skiers, backpackers and adrenaline junkies with snow boards in tow mill about. [Sydney Morning Herald]
The bad news is that old tricks—keyword stuffing, link-swapping, writing junky articles—and unethical tricks are increasingly blending. [Globe and Mail]
One former boss also had developed a practice of fixing up old service stations, so Allen learned to see past junky exteriors. [AZ Central]
Meanwhile, European junk has also been getting, well, junkier. [Financial Times]