adj. & n.
adj. 1 a serious, weighty, important (a grave matter). b dignified, solemn, sombre (a grave look). 2 extremely serious or threatening (grave danger). 3 (of sound) low-pitched, not acute.
n. = grave accent. grave accent a mark (`) placed over a vowel in some languages to denote pronunciation, length, etc., orig. indicating low or falling pitch. gravely adv. graveness n.
[ F grave or L gravis heavy, serious ]