Shiva Purana

siva.sh/siva-purana/saturda-samhita/8/47

विश्वं भर्तुं समर्थोसि भीषणाद्भैरवः स्मृतः ।। त्वत्तो भेष्यति कालोऽपि ततस्त्वं कालभैरवः ।। ४७ ।।

sanskrit

You are called Bhairava because you are of terrifying features and you are capable of supporting the universe. Since even Kāla is afraid of you, you are called Kālabhairava.

english translation

vizvaM bhartuM samarthosi bhISaNAdbhairavaH smRtaH || tvatto bheSyati kAlo'pi tatastvaM kAlabhairavaH || 47 ||

hk transliteration by Sanscript