electronic computer vs computing machine

electronic computer and computing machine both are nouns.

Word	Noun	Adjective	Verb	Adverb
electronic computer	Yes	No	No	No
computing machine	Yes	No	No	No

As nouns, electronic computer and computing machine are synonyms defined as:

electronic computer and computing machine: a machine for performing calculations automatically

Other synonyms of electronic computer include computer, computing device, data processor, information processing system.

electronic computer (noun)	computing machine (noun)
a machine for performing calculations automatically	a machine for performing calculations automatically