The most common and most likely answer to this crossword clue is the 8 letter word THEREMIN
T
H
E
R
E
M
I
N
More clues leading to the result THEREMIN
- Mere hint about unusual instrument
- Electronic instrument present, first of many in metal
- Within that location round Maidenhead you’ll find an instrument
- Instrument here, Max?
- ‘The REM Introduction’ begins with eerie instrument
- Instrument the miner played
- 'The REM Introduction' begins with eerie instrument
- Left here mindfully clutching instrument
- Meitner and Hahn’s first fantastic instrument
Buddy explains!

The straight part
We know that "eerie instrument" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case eerie instrument = theremin.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 THEREMIN mean?
THEREMIN noun- An electronic musical instrument that generates sound of varying pitch and volume depending on the proximity of the musician’s hands to two antennae mounted on the instrument.