The most common and most likely answer to this crossword clue is the 7 letter word MATURER
I've seen this crossword clue in The Times
M
A
T
U
R
E
R
Buddy explains!

The straight part
We know that "More experienced" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case more experienced = maturer.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 MATURER mean?
MATURER adjective- Fully developed; grown up in terms of physical appearance, behaviour or thinking; ripe.
- Brought to a state of complete readiness.
- Profound; careful.
- Come to, or in a state of, completed suppuration.
- Suitable for adults only, due to sexual themes, violence, etc.
- One who brings to maturity.