The most common and most likely answer to this crossword clue is the 10 letter word ENTHUSIAST
I've seen this crossword clue in The Daily Telegraph
E
N
T
H
U
S
I
A
S
T
More clues leading to the result ENTHUSIAST
- It’s a nut; he’s ebullient
- Hit tunes as recollected by fan
- Lover of criminal eats in housing like this
- Fan in seat wriggling about so
- Fan in seat, wriggling about so
- Strangely hesitant to accept American supporter
- Some sportsmen, thus, I astonished as fan
- Gourmet perhaps accordingly eats in, oddly outside
- Admirer in a suit sent misguidedly around hospital
- Surprisingly taut, she’s in buff!
Buddy explains!

The straight part
We know that "Admirer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case admirer = enthusiast.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 ENTHUSIAST mean?
ENTHUSIAST noun- A person filled with or guided by enthusiasm.
- A person exhibiting over-zealous religious fervour.