Definition of lapse verb from the Oxford Advanced Learner's Dictionary

lapse

verb
læps
 
; læps
 
 
1 [intransitive] (of a contract, an agreement, etc.) to be no longer valid because the period of time that it lasts has come to an endShe had allowed her membership to lapse.The treaty lapsed in 1995.2 [intransitive] to gradually become weaker or come to an end
Synonym
expire
His concentration lapsed after a few minutes.This custom had lapsed over the years.
3 [intransitive] lapse (from something) to stop believing in or practising your religionHe lapsed from Judaism when he was a student.lapsed
 
;
 
adjective [only before noun]a lapsed subscriptionlapsed faitha lapsed Catholic
Phrasal verbs

lapse into something

1 to gradually pass into a worse or less active state or conditionto lapse into unconsciousness/a comaShe lapsed into silence again.2 to start speaking or behaving in a different way, often one that is less acceptableHe soon lapsed back into his old ways.