Is there an opposite term for [sic]?

Solution 1:

Square brackets are used for interpolations and clarifications from the author and can enclose arbitrary meta-text (though this normally kept short). Examples are:

• negative press covfefe [sic]
• she wrote "you shall go to the ball" [my emphasis]
• she wrote "you shall go to the ball" [author's italics]
• The earth is round [editor's note: corrected from previous edition]

So you could simply use "[paraphrased]", "[translated]" or, dare I say, "[not sic]" as the "opposite" to "sic" to add clarification.

Depending on the situation it may be appropriate to interpolate the paraphrasing itself with the source text using square brackets. E.g.:

He said "the smart fridge is cool [fashionable]" without the intention of humour

The Chicago Manual of Style (Section 13, 16th Edition) has recommendations on using bracket notation, translations and paraphrasing.

Solution 2:

[sic] sic erat scriptum - meaning - thus was it written, in reference to a word that was as it was spelt, could be archaic, foreign or a misspelling, etc. There are no antonym for thus so the opposite would have to be 'Nec scriptum' ‘Nor was it written’