The most common and most likely answer to this crossword clue is the 5 letter word FRAIL
I've seen this crossword clue in The Guardian
F
R
A
I
L
More clues leading to the result FRAIL
- Female beside bar easily tempted
- Fail outside right that's easily injured
- Miss capturing rook — feeble!
- Weak, loud liar going into retirement
- Weak and unable to succeed outright
- Apparently stream will be curtailed for thirty days
- Infirm female to complain loud and long
- Weak part of cliff railway
- Fine bird hobbling around?
- Weak female needs to get on track
Buddy explains!

The straight part
We know that "Weak" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case weak = frail.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 FRAIL mean?
FRAIL noun- A basket made of rushes, used chiefly to hold figs and raisins.
- The quantity of fruit or other items contained in a frail.
- A rush for weaving baskets.
- A girl.
- To play a stringed instrument, usually a banjo, by picking with the back of a fingernail.
- Easily broken physically; not firm or durable; liable to fail and perish
- Weak; infirm.
- Mentally fragile.
- Liable to fall from virtue or be led into sin; not strong against temptation; weak in resolution; unchaste.