Used when quoting someone directly (usually in newspapers) and placed after the person being quoted makes a spelling error. The journalist/writer inserts (sic) to inform the reader that they aware of the spelling error but left it that way as to keep the quote verbatim

This is usually used for written quotes ie. letters

When some little bitchboy is acting like a little tiny pee pee poo poo baby and messing up the group plans.

Said in Context

Used in journalism when someone uses slang or misspeaks and the author doesn't correct it to keep the quote intact.

(sic) (Latin for "thus") is a bracketed expression used to indicate that an unusual spelling, phrase, or any other preceding quoted material is intended to be read or printed exactly as shown (rather than being an error) and should not be corrected. When found in a French document, (sic) stands for "Sans Intention Comique" (without comic intention) meaning that even if the preceding text could be understood as funny, it was not meant to be. It is used by writers quoting someone to alert the reader to the fact that an error or other weirdness in the quoted material is in the original, and not an error of transcription. "Sic" is almost always enclosed in parentheses.

A simple way to remember what it means is to consider sic as a pnemonic for 'spelt in context'.

1) also (sic); used when quoting someone and the person being quoted made a spelling error. This shows that the writer is aware of the mistake but doesn't correct it in order to quote properly.

2) used in chats and forums to point out that someone has made a dumb or disgusting remark. Also used to point out spelling and/or grammar mistakes or annoying txt tlk.
Can be used with or without square brackets.

Used in lieu of "attack," and used in association with the aggressive actions of someone or something, especially a dog.

A friendly term used by fans of Slipknot (Maggots) to basically say "stay cool" or "stay the same". Originated from the actual song by Slipknot called "(sic)".