vomit
喀 centers on the physical act of vomiting, specifically the sound or action of expelling something from the mouth.
喀 combines 口 (mouth) with 客, which likely contributes the sound カク. The character is used for the sound of vomiting or coughing up.
The mouth radical 口 beside 客 (guest) suggests an unwelcome guest leaving through the mouth: vomiting.
For カク, imagine a guest (客, カク) suddenly vomiting; the sound of the guest's retching is a harsh 'kak' that matches カク.