What lazy person did? One had been in front (5)
I believe the answer is:
idled
'what lazy person did?' is the definition.
(to idle is to be lazy)
'one had been in front' is the wordplay.
'one had' becomes 'Id' ('I'd' can mean 'one had').
'been in front' becomes 'led' (to lead is to go in front).
'id'+'led'='IDLED'
(Other definitions for idled that I've seen before include "Did lounge" , "pottered" , "relaxed" , "Was lazy" , "not worked" .)