wash out vs weaken

wash out and weaken both are verbs.

Word	Noun	Adjective	Verb	Adverb
wash out	No	No	Yes	No
weaken	No	No	Yes	No

As verbs, weaken is a hypernym of wash out; that is, weaken is a word with a broader meaning than wash out:

wash out (verb)	weaken (verb)
deplete of strength or vitality	become weaker
lose color in the process of being washed	lessen the strength of
drain off the color in the course of laundering	reduce the level or intensity or size or scope of
remove by the application of water or other liquid and soap or some other cleaning agent	lessen in force or effect
wear or destroy by the force of water	destroy property or hinder normal operations
wash free from unwanted substances, such as dirt
prevent or interrupt due to rain