[ 'alɪbʌɪ ]
■ noun ( plural ~s ) a claim or piece of evidence that one was elsewhere when an alleged act took place.
↘ informal an excuse.
■ verb ( ~s , ~ing , ~ed ) informal provide an ~ for.
Origin
C17: from L., 'elsewhere'.
Usage
The word ~ means ‘an assertion by a person that they were elsewhere’. In the 20th century a new sense arose with the meaning ‘an excuse’: this is still regarded as incorrect by some traditionalists.