WOOCOMMERCE 2.0
For those of you who have upgraded to WooCommerce 2.0, modify this file:
woocommerce/classes/abstracts/abstract-wc-product.php
As suggested by boluo33
“There are three instances of:
$availability = __(‘Out of stock’, ‘woocommerce’);
within the file.”
Change all three ‘Out of Stock’ to whatever you so desire. (In my case, I made it ‘ ‘, so that nothing shows and purchasing is simply unavailable). Cheers.