They watch actors step out (10)
I believe the answer is:
spectators
'they watch' is the definition.
Although both the answer and 'watch' are nouns, they are not in the same form of the noun.
'actors step out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'actors'+'step'='actorsstep'
'actorsstep' anagrammed gives 'SPECTATORS'.
Can you help me to learn more?
(Other definitions for spectators that I've seen before include "Witnesses" , "Those watching" , "Viewers" .)