'gush' originates from English (early modern), probably from an echoic or imitative origin reflecting a sudden flow or sound; recorded forms include 'gush' and earlier 'gushen'.

'gush' changed from earlier forms such as Middle English 'gushen' (or dialectal variants) and was recorded in the 16th century, eventually stabilizing as the modern English 'gush'.

Initially it meant 'to pour or rush out suddenly' (a literal sense for liquids); over time the word's use expanded metaphorically to mean 'to speak or display emotion effusively', which is a primary modern sense.