The most common and most likely answer to this crossword clue is the 13 letter word DOWN-TO-EARTH
I've seen this crossword clue in The Times
D
O
W
N
-
T
O
-
E
A
R
T
H
Buddy explains!
The straight part
We know that "Grounded" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case grounded = down-to-earth.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 DOWN-TO-EARTH mean?
DOWN-TO-EARTH adjective- Practical; realistic; pragmatic.