Haircut is usually a term for taking a reduced return on an existing investment that is otherwise unlikely to pay off - for example many European banks have taken a haircut of upto 50% on Greek government bonds, otherwise the greek government would leave the Euro, default anyway and take its chances.

Said haircut of course then stuffs their balance sheets, so they need bailing out, from for example Spainish government, which then cannot payout its loans and threatens a haircut to its investors. Who are the same damn banks it just bailed out.

This leads to two situations - one ECB chief saying it will pay anything to anyone to stop this idiocy, just ask. And two, the philosophical approach to wealth "hair today, gone tomorrow"

While the term has more specific meanings in finance, "haircut" it has been generalized to often mean "a small paycut".

Wiki page with more info: http://en.wikipedia.org/wiki/Haircut_%28finance%29

It's a Valley-ism - but yes, "haircut" simply refers to a (substantial) pay cut.

Haircut = any asset monetized below par value (100%)