Portmanteau of 'front' and 'monkey', combined to form a colloquial term for one who works at the front counter of a business. Normally a descriptive noun, or an informal address to be followed by shouting or threats. Shortened to 'fronkey' for ease of pronunciation.
Individuals are called so because they normally operate near the front entrance of the business, habitually smell of/consume otherwise unpalatable foods, make unreasonable amounts of noise, and willfully disorganize their work area while doing nothing of particular skill or value.
Hey, fronkey! Get back to the till and shut up.