sourpusssour‧puss /ˈsaʊəpʊs $ ˈsaʊr-/ noun [countable] old-fashioned 
someone who complains a lot and is never happy or satisfied
someone who complains a lot and is never happy or satisfied- inexpertly
- inexplicable
- inexplicably
- inexpressible
- inexpressibly
- inexpressive
- in extremis
- inextricable
- inextricably
- infallibility
- infallible
- infallibly
- infamous
- infamously
- infamy
- infancy
- infant
- infanticide
- infantile
- infantile paralysis
- infant mortality rate
- infantry
- infantryman
- infatuated
- infatuation