A term used to express annoyance or shock, can be used as an alternative to cursing. When used with a high pitched tone and an elongated vowel can be humourous and mocking. Also used as an insult. Macgee can also be added for effect.
Cowsie: I'm late for next lesson!
Friend: Oh Shiiiiiiiilters!
Man: Oh shilters look what you've done now!
Man: Oops! I dropped your vase.
Friend: Oh you stupid shiiiiilters!
Man: Oh Shilters Macgee!