This is a indept knowledge on The Almighty lord.
Lord Bhairav is an fierce incarnation of Lord Shiva.
Vigyan Bhairav or Bhairav Tantra text defines Bhairav as
Bhaya sarvan ravayati sarvado -vyapako khile
Iti bhairavo shbdasya santatocharacchivah
“Bhairav is one who with fear (bhaya) makes every thing resound (ravayati) and who pervades the entire universe. He who utters this word ‘Bhairav ‘unceasingly becomes Shiva”
The first syllabus ‘Bhai ‘ means fear and also means refulgent light and both meanings refer the nature of Bhairav