waiting vs ready and waiting

waiting is a noun but ready and waiting is not a noun.

Word	Noun	Adjective	Verb	Adverb
waiting	Yes	Yes	No	No
ready and waiting	No	Yes	No	No

As adjectives, waiting and ready and waiting are synonyms defined as:

waiting and ready and waiting: being and remaining ready and available for use

waiting (noun)	ready and waiting (noun)
the act of waiting (remaining inactive in one place while expecting something)

waiting (adjective)	ready and waiting (adjective)
being and remaining ready and available for use	being and remaining ready and available for use