Circus act intoxicated by telegram (4,4)
I believe the answer is:
high wire
'circus act' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'intoxicated by telegram' is the wordplay.
'intoxicated' becomes 'high' (similar in meaning).
'by' says to put letters next to each other.
'telegram' becomes 'wire' (synonyms).
'high'+'wire'='HIGH WIRE'
Can you help me to learn more?
(Other definitions for high wire that I've seen before include "Tightrope for acrobats" , "Elevated tightrope" .)