The most common and most likely answer to this crossword clue is the 4 letter word MOLE
I've seen this crossword clue in Financial Times
M
O
L
E
More clues leading to the result MOLE
- Spot undercover agent
- Spot unwanted visitor in the garden
- The French supporting second breakwater
- Spy additional line for resistance
- Recalled Michelangelo mixing a little spot of pigment
- Spy and his boss, say, getting Spanish approval
- Causeway in beauty spot
- Spy in a spot
- Spot or spy a breakwater
- How to work with the foreign “author” of a 23
Buddy explains!

The straight part
We know that "Causeway/beauty spot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case causeway/beauty spot = mole.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MOLE mean?
MOLE noun- A pigmented spot on the skin, a naevus, slightly raised, and sometimes hairy.
- Any of several small, burrowing insectivores of the family Talpidae.
- Any of the burrowing rodents also called mole rats.
- An internal spy, a person who involves himself or herself with an enemy organisation, especially an intelligence or governmental organisation, to determine and betray its secrets from within.
- A kind of self-propelled excavator used to form underground drains, or to clear underground pipelines
- A type of underground drain used in farm fields, in which a mole plow creates an unlined channel through clay subsoil.
- A moll, a bitch, a slut.
- A massive structure, usually of stone, used as a pier, breakwater or junction between places separated by water.
- A haven or harbour, protected with such a breakwater.
- An Ancient Roman mausoleum.
- In the International System of Units, the base unit of amount of substance; the amount of substance of a system which contains as many elementary entities (atoms, ions, molecules, etc.) as there are atoms in 0.012 kg of carbon-12. Symbol: mol. The number of atoms is known as Avogadro’s number.
- A hemorrhagic mass of tissue in the uterus caused by a dead ovum.
- One of several spicy sauces typical of the cuisine of Mexico and neighboring Central America, especially the sauce which contains chocolate and which is used in cooking main dishes, not desserts.