The most common and most likely answer to this crossword clue is the 8 letter word IMITATOR
I've seen this crossword clue in The Times
I
M
I
T
A
T
O
R
More clues leading to the result IMITATOR
- I’m one having volunteers to run copier
- Mimic — one getting duty list backed by Cambridge college
- Somewhat contrary parrot, a timid parrot
- One taking someone off duty list tiny boy and I set up
- Parrot‘s claim to be the main attraction on a hill
- Working at it, Miro must be an impressionist
- Setter going to university before new art eclipses old impressionist
- Writer’s computing work schedule? Wrong way round, using copier
- Copyist, having removed margins, limits data form
- I take off from island with German ace, going over to Rome initially
Buddy explains!

The straight part
We know that "Mimic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mimic = imitator.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 IMITATOR mean?
IMITATOR noun- One who imitates or apes another.