What is the meaning of good god gertie what a gash?

The phrase "good god gertie what a gash" is likely an exclamation expressing shock or surprise. "Good god" is an interjection used to convey strong emotions, while "gertie" is a colloquial term that may be used to add emphasis. "Gash" is a derogatory term referring to a long, deep cut or wound. Overall, the phrase conveys a sense of astonishment or disbelief at a situation or event.