ectomorph

/ˈɛktoʊˌmɔrf/
noun
  1. A person with a body type that is naturally thin, with little body fat and muscle, and a fast metabolism.
    • Ectomorphs often find it hard to build muscle even with regular exercise.
    • The fitness trainer designed a special diet for her ectomorph client to help him gain mass.
    • As an ectomorph, he could eat a lot without gaining weight.
Antonyms
What does "ectomorph" mean? | whatsthatwordmean | whatsthatwordmean