sex gland vs ductless gland

sex gland and ductless gland both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex gland	Yes	No	No	No
ductless gland	Yes	No	No	No

As nouns, ductless gland is a hypernym of sex gland; that is, ductless gland is a word with a broader meaning than sex gland:

sex gland: a gland in which gametes (sex cells) are produced
ductless gland: any of the glands of the endocrine system that secrete hormones directly into the bloodstream

Other hypernyms of sex gland include endocrine, endocrine gland.

sex gland (noun)	ductless gland (noun)
a gland in which gametes (sex cells) are produced	any of the glands of the endocrine system that secrete hormones directly into the bloodstream