WordNet sense 1 (an imperfection in a device or machine):

fault, flaw

WordNet sense 2 (a failing or deficiency):

shortcoming

WordNet sense 3 (a mark or flaw that spoils the appearance of something (especially on a person's body)):

blemish, mar

WordNet sense 4 (desert (a cause, a country or an army), often in order to join the opposing cause, country, or army):

desert, desert