Contraction of the affirmative expletive phrase "shit yeah". Used to avoid saying a curse word in social situations where vulgarity might be frowned upon or in casual speech to shorten the phrase. Pronounced with the second syllable rising higher in pitch than the first.
Example 1:
Since this is a holiday weekend, should we close the office at 3pm today?
Sh'yeah!
Example 2:
Do you want to ditch these losers and go get a burrito?
only used in the context of describing something of the utmost importance and fantasticness that happened recently. When using this word, be sure to employ emphasis and facial expression showing excitement, amusement and even bewilderment.