Definitions:

1. Quality of being renowned or celebrated for greatness, excellence, or fame. NOUN
   • The illustriousness of the scientist's career was recognized with numerous awards and honors.
2. Refers to the quality of being highly distinguished, well-known, or respected, often due to remarkable achievements, excellence, or a notable reputation. NOUN
   • His name is synonymous with illustriousness in the world of classical music.
3. The property possessed by something or someone of outstanding importance or eminence. NOUN
   • The university is known for its illustriousness in the field of research and innovation.
4. The state or quality of being illustrious. NOUN
   • The illustriousness of her career in medicine earned her a place in the hall of fame.

Synonyms:

• eminence
• fame
• greatness
• honor
• preeminence
• prestige
• prominence
• stature
• status