The most common and most likely answer to this crossword clue is the 4 letter word IDLY
I've seen this crossword clue in Financial Times
I
D
L
Y
More clues leading to the result IDLY
- I delay every so often; it’s how I behave?
- One facing delay regularly in lazy mode
- Indeed, lazy on vacation — behaving like this?
- Writer had vacated library in vain
- One intermittent delay, with no particular purpose
- Rosa Klebb would kick stuffing out of 9 for no particular reason
- Ideologically disheartened without thinking
- Find play oddly cut, in trifling kind of way
- How not to get things done, acting like Jack in pantomime?
- Something consumed casually
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 = idly.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 IDLY mean?
IDLY adverb- In an idle manner.
- Without specific purpose, intent or effort.