1. (noun) the quality of being valid and rigorous

• cogency
• rigor
• validity

2. (noun) something hard to endure

• asperity
• grimness
• hardship
• rigor
• rigorousness
• rigourousness
• severeness
• severity

3. (noun) excessive sternness

• hardness
• harshness
• inclemency
• rigor
• rigorousness
• rigourousness
• severeness
• severity
• stiffness

1. (noun) the quality of being valid and rigorous

• believability
• credibility
• credibleness

2. (noun) something hard to endure

• difficultness
• difficulty

3. (noun) excessive sternness

• sternness
• strictness

1. (noun) something hard to endure

• sternness

1. (noun) the quality of being valid and rigorous

• rigorous
• strict
• valid

2. (noun) something hard to endure

• grim
• inexorable
• relentless
• stern
• unappeasable
• unforgiving
• unrelenting
• severe
• terrible
• wicked

3. (noun) excessive sternness

• abrasive
• harsh
• hard
• tough
• harsh
• rough
• inclement
• rigorous
• rigorous
• stringent
• stringent
• tight
• tight
• rigorous
• strict
• severe
• severe
• spartan
• spartan