Gump (Portmanwho?)

1.) Gump

2.) Gump- combination of "gas pump"

3.) People would mostly think I was messing around when I used it around them, in the limited times "gas pump" was appropriate in context.  I think gas pump is a phrase that is so engrained in people's minds that it is awkward to think of that object and refer to it as anything else.  I also think "gump" is a cool way to say it though if it did catch on over time.