guesswork vs dead reckoning

guesswork and dead reckoning both are nouns.

Word	Noun	Adjective	Verb	Adverb
guesswork	Yes	No	No	No
dead reckoning	Yes	No	No	No

As nouns, guesswork and dead reckoning are synonyms defined as:

guesswork and dead reckoning: an estimate based on little or no information

Other synonyms of guesswork include guess, guessing, shot.

guesswork (noun)	dead reckoning (noun)
an estimate based on little or no information	navigation without the aid of celestial observations
	an estimate based on little or no information