devout (adj.)

c. 1200, of persons, "yielding reverential devotion to God," especially in prayer, "pious, religious," from Old French devot "pious, devoted, assiduous" (Modern French dévot) and directly from Latin devotus "given up by vow, devoted" (source also of Spanish and Portuguese devoto), past participle of devovere "dedicate by vow" (see devotion). Of actions, "expressing devotion or piety," late 14c. Meaning "sincere, solemn" is from mid-15c. Related: Devoutly; devoutness.