The most common and most likely answer to this crossword clue is the 2 plus 7 letter word ON IMPULSE
I've seen this crossword clue in The Daily Telegraph
O
N
I
M
P
U
L
S
E
More clues leading to the result ON IMPULSE
- Instinctively ring home about spasmodic heart beat
- Emulsion paint originally spattered without thinking
- Spoil menu stupidly and thoughtlessly
- Spontaneously translated “em, upsilon”
- Showing sign of life, Orlando’s dropped in without thinking
- Without thinking, I slump unsteadily in one
- Smile upon frolic that’s spontaneous
Buddy explains!
The straight part
We know that "Without thinking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case without thinking = on impulse.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.