Nouns

(n)clefta split or indentation in something (as the palate or chin)
(n)crack, cleft, crevice, fissure, scissurea long narrow cleft

Adjectives

(s)cleftsplit or divided“he had a cleft chin and strong jaw”, “the infant was born with a double harelip and cleft palate”, “a cleft stick”
(s)cleft, dissectedhaving one or more indentations reaching nearly to the midrib