A single man or woman who is attracted to a married man or woman and often attempts to engage said man or woman into a relationship (sexual or otherwise) with him or her.
"When I'm not doing homework or trolling Facebook, I'm often found being a ring sniffer men get lonely too!"

"There goes John... Doesn't he know that girl is married to an ex-navy seal?"
"Bro--he's in the zone. Hardcore ring sniffing.. He's going to end up dead!"
by small wonder April 8, 2014
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