The most common and most likely answer to this crossword clue is the 4 letter word WAIF
I've seen this crossword clue in Financial Times
W
A
I
F
More clues leading to the result WAIF
- Slender model debuts in Western action in film
- Homeless child would appear in front, first of all
- Child abandoned with frequency around main road
- Spouse almost hugs a poor child
- Skinny young model – mostly pale condition
- Stray with a condition
- Homeless child distressed waitress with note
- Neglected issue with a celebrated poem
- Women’s Aid initially provided for homeless child
- Water, accommodation primarily provided for stray
Buddy explains!

The straight part
We know that "poor child" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case poor child = waif.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 WAIF mean?
WAIF noun- A castaway; a homeless child.
- (of a plant outside its native range) A plant that has been introduced but is not persistently naturalized.
- Goods found of which the owner is not known; originally, such goods as a pursued thief threw away to prevent being apprehended, which belonged to the king unless the owner made pursuit of the felon, took him, and brought him to justice.
- Hence, anything found, or without an owner; that which comes along, as it were, by chance.