Cryptic crossword clue
Spooner's claptrap displayed aloft at its peak 4-5

The most common and most likely answer to this crossword clue is the 10 letter word FULL-BLOWN

I've seen this crossword clue in The Times
F
U
L
L
-
B
L
O
W
N

Buddy explains!

The straight part
We know that "at its peak" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case at its peak = full-blown.
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 FULL-BLOWN mean?

FULL-BLOWN adjective
  1. Completely developed or formed.
  2. At the peak of blossom; ripe.
  3. Filled with wind; puffed up.

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