The most common and most likely answer to this crossword clue is the 8 letter word FIDGETED
I've seen this crossword clue in Financial Times
F
I
D
G
E
T
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D
More clues leading to the result FIDGETED
Buddy explains!
The straight part
We know that "Looked nervous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case looked nervous = fidgeted.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 FIDGETED mean?
FIDGETED verb- To wiggle or twitch; to move around nervously or idly.
- To cause to fidget; to make uneasy.