wash out vs rain out

wash out and rain out both are verbs.

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

As verbs, wash out and rain out are synonyms defined as:

wash out (verb)	rain out (verb)
deplete of strength or vitality	prevent or interrupt due to rain
lose color in the process of being washed
drain off the color in the course of laundering
remove by the application of water or other liquid and soap or some other cleaning agent
wear or destroy by the force of water
wash free from unwanted substances, such as dirt
prevent or interrupt due to rain