weight down vs saddle

weight down is not a noun while saddle is a noun.

Word	Noun	Adjective	Verb	Adverb
weight down	No	No	Yes	No
saddle	Yes	No	Yes	No

As verbs, saddle is a hyponym of weight down; that is, saddle is a word with a more specific, narrower meaning than weight down:

Other hyponyms of weight down include overburden, plumb.

weight down (noun)	saddle (noun)
	posterior part of the back of a domestic fowl
	a seat for the rider of a horse or other animal
	a seat for the rider of a bicycle
	a piece of leather across the instep of a shoe
	cut of meat (especially mutton or lamb) consisting of part of the backbone and both loins
	a pass or ridge that slopes gently between two peaks (is shaped like a saddle)

weight down (verb)	saddle (verb)
weight down with a load	impose a task upon, assign a responsibility to
	put a saddle on
	load or burden; encumber