An inexplicable, curiously concerning behaviour frequently demonstrated by individuals with near-pathologic emotional, physical (and possibly spiritual) attachment to a specific vehicle, often a motorcycle--that, once relinquished either by sale or trade, creates such tremendous internal loss-aversion that any and all measures are taken to restore possession, often at financial detriment.
Ok, that's the FIFTH fuckin' time that he's either traded or sold that damn Harley only to chase down the new owner in remorse. Each time he's lost money, time and self-respect...but it sure is entertaining watching the motoreturnus profundus!
Literally translates as "of the Depths" or, with modification, "from the depths". Any reference to a being emerging from the pit of dispair to greater things is entirely contextual.
Oscar Wilde famously wrote a long letter - later titled "De Profundis" - after his release from Reading Gaol.