The most common and most likely answer to this crossword clue is the 4 letter word WAIL
W
A
I
L
More clues leading to the result WAIL
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The straight part
We know that "Keen" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case keen = wail.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 WAIL mean?
WAIL noun- A prolonged cry, usually high-pitched, especially as of grief or anguish.
- Any similar sound as of lamentation; a howl.
- A sound made by emergency vehicle sirens, contrasted with "yelp" which is higher-pitched and faster.
- To cry out, as in sorrow or anguish.
- To weep, lament persistently or bitterly.
- To make a noise like mourning or crying.
- To lament; to bewail; to grieve over.
- To perform with great liveliness and force.
- To strike the skin in such a way as to produce a wale or welt.
- To give a surface a texture of wales or welts.
- To choose, select.