Definition of "slip away"

slip away

verb
third-person singular simple present slips away, present participle slipping away, simple past and past participle slipped away
1. To leave a place, or a gathering, without being noticed.
  Quotations
  But when Bobbie crept down later to bring up her presents--for she felt she really could not be separated from them all night--Mother was not writing, but leaning her head on her arms and her arms on the table. I think it was rather good of Bobbie to slip quietly away, saying over and over, "She doesn't want me to know she's unhappy, and I won't know; I won't know." But it made a sad end to the birthday.
  1906, Edith Nesbit, The Railway Children, Chapter 4: The engine-burglar
2. To pass quickly, almost unnoticed. (of time)
  Quotations
  But with every word she was drawing further and further into herself, so he gave that up and only the dead dream fought on as the afternoon slipped away, trying to touch what was no longer tangible, struggling unhappily, undespairingly, toward that lost voice across the room.
  1925, F. Scott Fitzgerald, chapter 7, in The Great Gatsby, page 144
3. To disappear; to elude one; to recede; to dwindle.
  Quotations
  What about love? / Don't you want someone to care about you? / What about love? / Don't let it slip away
  1985, Brian Allen, Sheron Alton, Jim Vallance, “What About Love”, in Heart‎, performed by Heart
  Scharner then headed a Dorrans free-kick against the crossbar, with Tchoyi unable to turn in the follow-up as the Baggies saw their hopes of salvaging a point slip away.
  2010 December 28, Kevin Darling, “West Brom 1 - 3 Blackburn”, in BBC‎
  And there are few better ways to enjoy the rugged bleakness of the fells than from a nice warm train, especially when the weather's constantly changing as the day slips away.
  2022 November 2, Paul Bigland, “New trains, old trains, and splendid scenery”, in RAIL, number 969, page 57
4. (euphemistic) To die peacefully.