I left data lying around, moderately carelessly (11)

I believe the answer is:

negligently

'carelessly' is the definition.
(I've seen this before)

'i left data lying around moderately' is the wordplay.
'left' becomes 'l' (common abbreviation).
'data' becomes 'gen' (I've seen this in other clues).
'lying around' shows that the letters should be reversed in order.
'moderately' becomes 'gently'.
'i'+'l'+'gen'='ilgen'
'ilgen' in reverse letter order is 'negli'.
'negli'+'gently'='NEGLIGENTLY'

(Another definition for negligently that I've seen is " carelessly".)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app