'Willing offering' in the Bible

'And when a man bringeth near a sacrifice of peace-offerings to Jehovah, to complete a vow, or for a willing-offering, of the herd or of the flock, it is perfect for a pleasing thing: no blemish is in it;

As to an ox or a sheep enlarged or dwarfed -- a willing-offering ye do make it, but for a vow it is not pleasing.