paying attention vs heedful

paying attention is a noun but heedful is not a noun.

Word	Noun	Adjective	Verb	Adverb
paying attention	Yes	Yes	No	No
heedful	No	Yes	No	No

As adjectives, paying attention and heedful are synonyms defined as:

paying attention and heedful: taking heed; giving close and thoughtful attention

Other synonyms of paying attention include attentive, thoughtful.

paying attention (noun)	heedful (noun)
paying particular notice (as to children or helpless people)

paying attention (adjective)	heedful (adjective)
taking heed; giving close and thoughtful attention	taking heed; giving close and thoughtful attention
	giving attention
	cautiously attentive