As like as not British old-fashioned spoken
The word "like" is short for "likely" in the sense of "probably". The first "as" can be excluded.
If someone says something will happen "as like as not", he/she means that it is probable for something to happen or there is a chance that something will be true.
As like as not, he will receive lots of gifts from his beloved ones on his next birthday.
Lisa is an avid reader. You would find her in the school library, immersing herself in a fiction book, as like as not.
He will pick you up for dinner, as like as not.
To have a likelihood of achieving something.
The phrase dates from the late 1800s.
A problem or difficult circumstance
I'm short-sighted, so forgetting my glasses is a real hair in the butter for my sight.