The most common and most likely answer to this crossword clue is the 4 letter word FAIL
I've seen this crossword clue in Financial Times
F
A
I
L
More clues leading to the result FAIL
- Feasible, occasionally, to come up short
- Let down smaller section of Irish party
- Break from female trouble
- Flunk when feeble, right to pull out
- Be unsuccessful in fighting against insurgency leaders, initially
- Become bankrupt following trouble
- Founder of football body I left
- Break down following trouble
- Designed to prevent accidents, note, if seal cracks
- Female isn’t well, a female with little energy certain not to conk out
Buddy explains!
The straight part
We know that "Let down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case let down = fail.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 FAIL mean?
FAIL noun- Poor quality; substandard workmanship.
- A failure (condition of being unsuccessful)
- A failure (something incapable of success)
- A failure, especially of a financial transaction (a termination of an action).
- A failing grade in an academic examination.
- To be unsuccessful.
- Not to achieve a particular stated goal. (Usage note: The direct object of this word is usually an infinitive.)
- To neglect.
- Of a machine, etc.: to cease to operate correctly.
- To be wanting to, to be insufficient for, to disappoint, to desert.
- To receive one or more non-passing grades in academic pursuits.
- To give a student a non-passing grade in an academic endeavour.
- To miss attaining; to lose.
- To be wanting; to fall short; to be or become deficient in any measure or degree up to total absence.
- To be affected with want; to come short; to lack; to be deficient or unprovided; used with of.
- To fall away; to become diminished; to decline; to decay; to sink.
- To deteriorate in respect to vigour, activity, resources, etc.; to become weaker.
- To perish; to die; used of a person.
- To err in judgment; to be mistaken.
- To become unable to meet one's engagements; especially, to be unable to pay one's debts or discharge one's business obligation; to become bankrupt or insolvent.
- That is a failure.
- A piece of turf cut from grassland.