moth [OE] In Anglo-Saxon times a moth was any parasitic pest such as a maggot or worm, especially the larva of the clothes moth. The name eventually extended to the adult clothes moth, and then to other similar insects. People were able to use naphthalene as a mothball to protect stored clothes from the 1890s until the substance was banned in 2008. By the 1920s in mothballs came to mean ‘unused but kept in good condition for future use’. Compare butterfly.