Equity withdrawal is remortgaging your house for a higher amount, and cashing in some of the equity.
If your mortgage is fairly low compared to the value of the property, then you can increase the mortgage on the house and bank the money. Effectively it is just a cheaper way of borrowing money than an average loan from a bank.
I wouldn't recommend it if there is any other way, because unlike a loan from the bank, it has a very long repayment period - 25 years or whatever the remaining mortgage term is.
But if you can still comfortably afford the repayments, and don't want to sell your house to pay off debts, then it is one way of getting through a temporary tough patch to avoid moving house.
Another way of doing this is a mortgage 'holiday'. This basically means that you don't pay anything into the mortgage for an agreed period with your bank, say a year. Meanwhile interest is still accruing on the mortgage, but will add to the overall amount owed, rather than having to be paid off immediately.
If you think that your job prospects are excellent in the long term and you feel that you just need to get over a small hiccup, then it is one option. But I wouldn't do it if you don't think a quick pick up is likely.