ectomorph ['ɛktəʊˌmɔːf] noun a person with a thin body build: said to be correlated with cerebrotonia (also from merriam webster: 1 : of or relating to the component in W. H. Sheldon's classification of body types that measures the body's degree of slenderness, angularity, and fragility)

cerebrotonia [ˌsɛrıbrəʊ'təʊnıə] noun a personality type characterized by restraint, alertness, and an intellectual approach to life: said to be correlated with an ectomorph body type