"second-hand"--(possible blend)

[Cohen, Gerald Leonard]

Original message from Jonathan Lighter, Jan. 21, 2005:

> Around 1979 I heard a student using "second-hand" to mean "second nature" : "You keep doing it till it becomes second-hand."
>
> Since then I've heard this many times. [...]
>
        *********

This may be a blend:
"...until it becomes second nature" + "until you know it like the back of your hand."

Gerald Cohen