The most common and most likely answer to this crossword clue is the 5 letter word CILIA
I've seen this crossword clue in Independent
C
I
L
I
A
Buddy explains!
The straight part
We know that "lashes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lashes = cilia.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 CILIA mean?
CILIA noun- Hairs or similar protrusions along the margin of a plant organ.
- A hairlike organelle projecting from a eukaryotic cell (such as a unicellular organism or one cell of a multicelled organism). These structures serve either for locomotion by moving or as sensors.
- One of the fine hairs along an insect's wing.