:ab
:unab
:map
:unmap
:map!
:unmap!
Remove input mode map (you may need to quote the character with CTRL-V ).
CTRL-V
The following characters are unused in command mode and can be mapped as user-defined commands:
g K q V v
^A ^K ^O ^W ^X
_ * \ =
(Note: the = is used by vi if Lisp mode is set. Different versions of vi may use some of these characters, so test them before using.)