Stay (6)
'stay' is the definition.
(I know that stay can be written as remain)
This is all the clue.
(Other definitions for remain that I've seen before include "stop behind?" , "Stay or continue to be" , "Don't leave (the EU?)" , "Survive" , "Stay (in position)" .)
'stay' is the definition.
(lingering is a kind of staying)
This is the entire clue.
(Other definitions for linger that I've seen before include "Hang back awhile" , "Remain for long" , "'Loiter, delay leaving (6)'" , "Hang about, don't be in a hurry to go" , "Dally, stay on" .)