One example of an 8-letter word ending with "ing" is "starting." It refers to the act of beginning something or initiating a process.
campaign, vacation
The word that can end in "ing" and relates to day is "daydreaming."
"Parenting."
what words end with ing for sun
understating
freezing,
The word is dawning.
avoidingbreakingcrawlingdrinkingenduringfloatingguessinghumoringinvitinglisteningmountingnoticingorderingpressingprintingquittingroastingstealingtreadingunendingvouchingwateringyielding
Coloring
Yes. Any word with the ending '-ing' is a verb.
dieting
Wrung, Slang