lough vs lake

lough and lake both are nouns.

Word	Noun	Adjective	Verb	Adverb
lough	Yes	No	No	No
lake	Yes	No	No	No

As nouns, lake is a hypernym of lough; that is, lake is a word with a broader meaning than lough:

lough (noun)	lake (noun)
Irish word for a lake	a body of (usually fresh) water surrounded by land
a long narrow (nearly landlocked) cove in Ireland	any of numerous bright translucent organic pigments
	a purplish red pigment prepared from lac or cochineal