The most common and most likely answer to this crossword clue is the 3 plus 5 letter word RED CROSS
I've seen this crossword clue in Independent
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More clues leading to the result RED CROSS
- Wine found next to hamper: that brings relief!
- Medical organisation is ruddy annoyed
- Charity gets one looking embarrassed and angry
- Unwelcome mark on a paper flag
- Communist not best pleased in humanitarian group
- Charity is embarrassed and angry
- Charity makes radical angry
- Medical helpers embarrassed and angry
- International team broke records at start of season
- Bolshevik put out flag
Buddy explains!

The straight part
We know that "humanitarian group" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case humanitarian group = red cross.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.