certainty

Firmness is a related term of certainty.

As nouns the difference between firmness and certainty

is that firmness is the state of being firm; strength; permanence; stability; hardness; resolution while certainty is the state of being certain.

Certainty is a related term of ease.

As nouns the difference between certainty and ease

is that certainty is the state of being certain while ease is the state of being comfortable or free from stress.

As a verb ease is

to free (something) from pain, worry, agitation, etc.

As a noun certainty

is the state of being certain.

As a letter x is

the twenty-fourth letter of the.

As a symbol x is

voiceless velar fricative.

As a noun certainty

is the state of being certain.

As an adjective predictable is

able to be predicted.

As a verb require

is (label) to ask (someone) for something; to request.

As a noun certainty is

the state of being certain.

As a noun certainty

is the state of being certain.

As an adjective false is

(label) one of two states of a boolean variable; logic.

As a noun certainty

is the state of being certain.

As an adjective undefined is

lacking a definition or value.

As nouns the difference between certainty and justification

is that certainty is the state of being certain while justification is a reason, explanation, or excuse which provides convincing, morally acceptable support for behavior or for a belief or occurrence.

As an adverb probably

is in all likelihood.

As a noun certainty is

the state of being certain.