The adjective antediluvian means someone or something that is extremely old-fashioned.

Synonyms are ancient, antique, old, or primitive.

The word origins in 1640s. It comes from Latin ante meaning “before” plus diluvium meaning “a flood”. It was coined by English physician Sir Thomas Browne (1605 – 1682). The noun meaning “person who levied before the flood” is from 1680s.

My teacher has some antediluvian ideas about the role of women.

There was humor about an antediluvian city ruled by intelligent reptiles.

The mean girls made her wear an antediluvian outfit at the party.

The adjective surreptitious means something that is done secretly, without anyone seeing or knowing.

Synonyms are clandestine, covert, furtive or unauthorized.

The word origins from Latin (middle 15th century) surrepticius meaning “stolen, furtive, clandestine”, from surreptus, past participle of surripere meaning “seize secretly, take away, steal, plagiarize”. It comes from sub meaning “from under” plus rapere meaning “to snatch”.

Their surreptitious glances at the audience made them feel more nervous.

Pia helped her classmate to complete their assignments in a surreptitious manner.

He made a surreptitious recording to catch them in the act.

The adjective insipid means something that doesn’t have a strong taste or energy.

Synonyms are banal, bland, innocuous, or vapid.

The word origins from Middle French (16th Century) insipide meaning “insipid”, and from Late Latin inspidus meaning “tasteless”. It comes from in- meaning “not” plus Latin sapidus meaning “tasty”, from sapere meaning “have a taste”. Figurative meaning “uninteresting, dull” was first recorded in English 1640s.

It tasted indescribably insipid and like warmed cardboard.

No one knows why they buy music with such insipid lyrics.

He is an insipid old bore in our first meet.

The adjective amorphous means something that has no clear shape or structure.

Synonyms are baggy, blobby, nebulous, or vague.

The word origins from Modern Latin (1731) amorphus, and from Greek amorphos meaning “without form, shapeless, deformed”. It comes from a- meaning “without” plus morphē meaning “form”.

Amorphous carbon is free and does not have any crystalline structure.

It is common to have an amorphous mass of buildings and highways.

Amorphous silicon is a low-cost material for solar cells.

The verb usurp means to take and hold something with force or violence.

Synonyms are arrogate, expropriate, steal or seize.

The word origins from Old French (14th century) usurper meaning “to (wrongfully) appropriate”, Latin usurpare meaning “make use of, seize for use” in later Latin “to assume unlawfully, trespass on” and usus meaning “a use”.

The thief usurped his necklace.

The burglar plans to usurp the safe in his neighbors house.

Dino’s original script for his book was usurped by his brother.

The noun zealot means a fanatic person who has extreme opinions about something, usually about religion or politics, and forcefully tries to influence the opinions of others. 

Synonyms are militant, fanatic, enthusiast, or activist.

The word origins from Late Latin (early 14th century) zelotes and from Greek zēlōtēs meaning “one who is a zealous follower” from zēlos meaning “zeal”. It does have an extended sense of “a fanatical enthusiast” first recorded in the 1630s.

She is professional and intelligent, yes, but she is also one of the worst kinds of zealot.

One of the downside of social media is that zealot people are literally everywhere.

I know a place that is run mostly by zealots.

The verb admonish is used to indicate someone did something wrong or against his duties and obligations. It is also used to give friendly advice or warning.

Synonyms are chide, rebuke, scold or warn.

The word origins from Vulgar Latin (mid. 14th century) amonesten meaning “remind, urge, exhort, warn, give warning” and admonere “bring to mind, remind (of a debt)”. The “d” in the word came from the Modern French admonester. The part monēre relates from English to monitor, monitory or “giving a warning”.

They were first admonished before they had to leave the room.

Before they went into the forest alone he admonished them to be careful.

The sign admonished to “mind the gap”.