When something attenuates, it lessens in size or intensity; it becomes thin or weakened.

A behemoth is monstrously large in size or power, such as a gigantic whale or corporation; sometimes this word is given a negative implication in the sense that a behemoth is so large that it is difficult or impossible to manage.

If something daunts you, it makes you worried about dealing with it because you think it will be very difficult or dangerous.

Debility is a state of being physically or mentally weak, usually due to illness.

Decrepitude is the state of being very old, worn out, or very ill; therefore, something or someone is no longer in good physical condition or good health.

A despot is a leader who has a lot of power and uses it in a cruel and unreasonable way.

Someone who is diffident is shy, does not want to draw notice to themselves, and is lacking in self-confidence.

A dilapidated building, vehicle, etc. is old, broken-down, and in very bad condition.

When one person eclipses another’s achievements, they surpass or outshine that person in that endeavor.

If you describe a person, group, or civilization as effete, you mean it is weak, exhausted, powerless, unproductive, and/or corrupt.

Efficacy is the ability or power to produce an expected effect or result.

A person or animal that is emaciated is extremely thin because of a serious illness or lack of food.

Someone who is feckless is incompetent and lacks the determination or skill to achieve much of anything at all in life.

If something is formidable, it is impressive in size, power, or skill; therefore, it can make you feel frightened, alarmed, or in awe because it is so powerful or difficult to deal with.

Something gargantuan is extremely large.

Something that is immutable is always the same and cannot be changed.

An impregnable opinion or feeling is very difficult to change.

Inconsequential matters are unimportant or are of little to no significance.

Someone who has an indomitable drive refuses to give up under any circumstances.

Something that is ineluctable is impossible to avoid or escape, however much you try.

The adjective inexorable describes a process that is impossible to stop once it has begun.

Something that inhibits you from doing something restricts or keeps you from doing it.

Someone, such as a performer or athlete, is inimitable when they are so good or unique in their talent that it is unlikely anyone else can be their equal.

Someone or something that is invulnerable cannot be harmed in any way; hence, they or it is completely safe or secure.

A juggernaut is a very powerful force, organization, or group whose influence cannot be stopped; its strength and power can overwhelm or crush any competition or anything else that stands in its way.

A leviathan is something that is very large, powerful, difficult to control, and rather frightening.

An organization or system that is a monolith is extremely large; additionally, it is unwilling or very slow to change or adopt something new.

If you have a nemesis, it is an opponent or rival whom you cannot beat or is a source of ruin that causes your downfall.

Numinous objects or places seem holy, spiritual, and possess a mysterious power, which make you feel that a spirit or god may be present.

A plenipotentiary is someone who has full power to take action or make decisions on behalf of their government in a foreign country.

Something’s potency is how powerful or effective it is.

A potentate is a ruler who has great power over people.

Something that is prodigious is very large, impressive, or great.

If you describe someone as redoubtable, you have great respect for their power and strength; you may be afraid of them as well.

Skittish persons or animals are made easily nervous or alarmed; they are likely to change behavior quickly and unpredictably.

A stricture can also be a severe criticism of what someone has said or done.

If you surmount a problem or difficulty, you get the better of it by conquering or overcoming it.

Something tenuous is thin, weak, and unconvincing.

To be timorous is to be fearful.

Something that is transcendent not only surpasses all others in quality, achievement, or significance, but exceeds normal limits or boundaries.

Someone is tremulous when they are shaking slightly from nervousness or fear; they may also simply be afraid of something.

Something that is trivial is insignificant, commonplace, of little value, or not important.

A thing or person that is unremitting is persistent and enduring in what is being done.

If you are unsurpassed in your field of study, you are the best—period.

The zenith of something is its highest, most powerful, or most successful point.