The most common and most likely answer to this crossword clue is the 3 letter word AHA
I've seen this crossword clue in Independent
A
H
A
More clues leading to the result AHA
- Articles about hotel leading to a surprised response
- I see Tonya Harding’s content
- Triumphant expression every second from rash lad
- That’s surprising — bathmat oddly missing
- Bingo’s a bit of a laugh
- Pathway regularly chosen causing surprised reaction?
- What I'm surprised to say you'll find in Sahara
- I get it‘s a sound made in mirth
- I’m surprised captain with prosthetic leg has no foot
- Triumphant expression from husband in Carmen?
Buddy explains!

The straight part
We know that "Triumphant expression" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case triumphant expression = aha.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 AHA mean?
AHA interjection- An exclamation of understanding, realization, invention, or recognition.
- An exclamation of surprise, exaltation, or contempt.