dead reckoning vs guessing

dead reckoning and guessing both are nouns.

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

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

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

Other synonyms of dead reckoning include guess, guesswork, shot.

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