means Staying somewhere or letting something persist longer than expected, often reluctant to end or move on.

from From the verb 'linger,' which descends from Middle English 'lengeren,' a frequentative of the older 'lengen' meaning 'to delay, prolong, or dwell.' That root traces back to Old English 'lengan,' 'to lengthen or tarry,' which is a cousin of 'long' — so to linger is, quite literally, to make a moment longer. The '-ing' simply turns the act of dragging time out into the quality of a thing that won't quite end.