The most common and most likely answer to this crossword clue is the 10 letter word RED-HANDED
I've seen this crossword clue in The Guardian
R
E
D
-
H
A
N
D
E
D
Buddy explains!
The straight part
We know that "In the act/(Act II, ii), like Macbeth" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in the act/(act ii, ii), like macbeth = red-handed.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 RED-HANDED mean?
RED-HANDED adjective- Showing clear evidence of guilt; in the act of wrongdoing.
- Deadly, bloody.
- With hands that are red from blood.