While you aren't wearing armor or wielding a Shield, your base Armor Class equals 10 plus your Dexterity and Wisdom modifiers.
Unarmored Defense
Raw data
{
"name": "Unarmored Defense",
"page": 101,
"level": 1,
"srd52": true,
"__prop": "classFeature",
"source": "XPHB",
"entries": [
"While you aren't wearing armor or wielding a {@item Shield|XPHB}, your base {@variantrule Armor Class|XPHB} equals 10 plus your Dexterity and Wisdom modifiers."
],
"className": "Monk",
"classSource": "XPHB",
"basicRules2024": true
}