this2 [+ adjective/adverb]
used to say how big, how much etc, when you are showing the size, amount etc with your hands:
The table's about this high and this wide.
You need to cut about this much off the end of the pipe.
2 [usually in questions and negatives] spoken
as good, bad, much etc as in the present situation:
I hadn't realised that things had got this bad.
I've never had this much money before.