Alarm has no time lapse (5)
I believe the answer is:
error
'lapse' is the definition.
(thesaurus)
'alarm has no time' is the wordplay.
'alarm' becomes 'terror' (I've seen this before).
'has no' suggests deleting specific letters.
'time' becomes 't'.
'terror' with 't' taken out is 'ERROR'.
(Other definitions for error that I've seen before include "Faulty judgement" , "wrongdoing" , "Blunder or mistake" , "Faux pas" , "Howler" .)