The most common and most likely answer to this crossword clue is the 13 letter word PATERNALISTIC
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The straight part
We know that "benevolent but intrusive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case benevolent but intrusive = paternalistic.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.
Crossword Answer definitions
PATERNALISTIC adjective- The quality of being paternal, i.e. like a father, e.g. characterized by behaving in benevolent and yet intrusive manner towards underlings
- Of, pertaining to, characteristic of or practicing paternalism