From Longman Dictionary of Contemporary Englishbe conspicuous by your/its absencebe conspicuous by your/its absenceTHEREused to say that someone or something is not somewhere where they were expected to be a group that were conspicuous by their absence from the awards ceremony → conspicuous
Examples from the Corpus
be conspicuous by your/its absence• If I have any qualification, it is that contemporary work is conspicuous by its absence. 