extravagant
忲 centers on excess and lack of restraint: being extravagant, wasteful, or overly indulgent.
忲 combines the heart radical 忄 with 太, which likely contributes the sound and the idea of excess or greatness, suggesting an extravagant heart or disposition.
The heart radical 忄 beside 太 (fat, great) suggests a heart that is too large or indulgent, leading to extravagant behavior.
For タイ, imagine an extravagant tie worn by someone with an overly indulgent heart: tie -> タイ.