Sorry, Joe-- it's not old-fashioned at all in my vocabulary. Young couples, when they are still innocent, I still describe as 'going together', even though the age of innocence has lowered steadily over the years.
I am afraid you will have to learn each 'old-fashioned' word just in case. I just finished dealing with a post asking about 'methinks', which is about as old-fashioned as you can get while remaining intelligible-- and yet it still pops up in conversation occasionally, albeit usually in a jocular manner.
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