1. HEEDLESSLY.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• eegardlessly,
• degardlessly,
• fegardlessly,
• tegardlessly,
• 5egardlessly,
• 4egardlessly,
• rwgardlessly,
• rsgardlessly,
• rdgardlessly,
• rrgardlessly,
• r4gardlessly,
• r3gardlessly,
• refardlessly,
• revardlessly,
• rebardlessly,
• rehardlessly,
• reyardlessly,
• retardlessly,
• regzrdlessly,
• regsrdlessly

• guardedly,
• genuineness,
• heartless,
• regardless,
• regard,
• hardness,
• hardly,
• regardlessness.

The adjective form of the word "regardlessly" is "regardless".