Delightful, delicious, delectable, luscious mean extremely pleasing or gratifying to the senses or to aesthetic taste.
Delightful, the least restricted in its application of these words, may refer to anything that affords keen, lively pleasure and stirs the emotions agreeably, whether the direct appeal is to the mind, the heart, or the senses.
Delicious commonly refers to sensuous pleasures, especially those of taste and smell, but may be applied to anything which is so delightful that one dwells upon it with sensuous gratification.
Delectable in its implications is often indistinguishable from delightful and especially from delicious, though it often suggests more refined or discriminating enjoyment.
The term is more often used than either delightful or delicious with a humorous or ironical connotation.
Luscious adds to delicious an implication of richness (as of flavor, fragrance, coloring, or sound). As applied to fruits, it suggests fullness of flavor and rich ripe juiciness.
Like delectable it may be used humorously or ironically, but it then commonly adds the implication of extravagance, exaggeration, or, more specifically, voluptuousness.