late 14c., "concerned with or pertaining to the function of nourishing," from Old French nutritif and directly from Medieval Latin nutritivus "nourishing," from nutrit-, past-participle stem of Latin nutrire "to nourish, suckle, feed," from PIE *nu-tri-, suffixed form (with feminine agent suffix) of *(s)nau- "to swim, flow, let flow," hence "to suckle," extended form of root *sna- "to swim." Meaning "having the property of nourishing, nutritious" is from early 15c.
