The Origin of "Cold Feet"

Meaning

To 'get cold feet' is to become disheartened or timid, losing one's previous enthusiasm or courage.

Origin

Why this term was coined isn't at all clear. On the face of it there doesn't seem to be any obvious connection with the literal meaning of cold feet and the meaning of the phrase.

There are a couple of citations of the phrase from 1896, including this from Stephen Crane's novel Maggie, a girl of the streets, 1896:

"I knew this was the way it would be. They got cold feet."

While bare footprints in the snow would make your feet cold, 
'Cold Feet' has nothing to do with the literal meaning

Apprehension or doubt strong enough to prevent a planned course of action.
A loss or lack of courage or confidence; an onset of uncertainty or fear.
To “have cold feet” is to be too fearful to undertake or complete an action.
A wave of timidity or fearfulness.
Loss or lack of courage or confidence.
Timidity that prevents the continuation of a course of action.