1 : to feel or express dejection or discontent : complain
2 : to long for something
This word immediately makes me think of "pining" for something, so I was pleased to scroll down to the etymology and find this issue addressed.
In longing, one can "repine over" something ("repining over her lost past"), or one can "pine for" something. The two words, used thus, mean close to the same thing, but not exactly. "Pining" is intense longing for what one once knew. "Repine" adds an element of discontent to any longing — an element carried over from its first sense ("to feel or express dejection or discontent").
This is fascinating—mostly because I feel like any type of longing implies a sense of discontent. I can't remember a time during which I PINED or REPINED for something and felt good about it.
(let's take another step back)
My general rule about regret is that it exists only in the eye of the beholder. Regret is merely a perception. If you believe you made a mistake, then, by all means, you have. But the mistake, the wrong decision, the moment of transgression, does not exist on a plane of its own as a mistake. It just exists as an action; regret is merely the foggy glass through which the action is observed. Open the window and you will find you see clearly.
Longing implies one feels she is lacking something and wishes to gain (or regain) that something. I am not denying my experiencing these feelings. But I will say that the moments are all laced with a layer of discontent. After all, if I were content, per se, I probably wouldn't be longing for anything.
I try (really hard) not to REPINE. I look fondly upon memories, but I can honestly say I don't want to go back to another less-complicated time, nor do I PINE for an imagined future in which things may be better, easier, more pleasurable.
I like now. I like today. I'll take it.