The most common and most likely answer to this crossword clue is the 7 letter word CLAPPED
I've seen this crossword clue in Financial Times
C
L
A
P
P
E
D
Buddy explains!

The straight part
We know that "Acclaimed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case acclaimed = clapped.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 CLAPPED mean?
CLAPPED verb- To strike the palms of the hands together, creating a sharp sound.
- To applaud.
- To slap with the hand in a jovial manner.
- To bring two surfaces together forcefully, creating a sharp sound.
- To come together suddenly with noise.
- To create or assemble (something) hastily (usually followed by up or together).
- To set or put, usually in haste.
- To shoot (somebody) with a gun.