Your mate, spouse, husband, wife, boyfriend, girlfriend, steady and/or lover. Used when you don't want to be too specific, or when the details are nobody's business.
Why's Roger always talking about his significant other? Why don't he just say girlfriend?
Combination of "statistically significant" and "significant other."
Since he spent twice as much time with Karen as with any of the other girls he was dating, his friends called Karen his statistically significant other.
a phrase used to describe the cunt or douche that you used to officially have a relationship with that is still part of your life for whatever stupid reason that you're coming up with.
I took my (in)significant other to lunch yesterday. Not five minutes had passed before she was correcting my grammar and telling me that I was eating with the wrong fork. I LIKE THE LITTLE FORK.