The three words that have a similar connotation to "illustrious" are:
- Renowned
- Notorious (Note: While "notorious" typically has a negative connotation, it can imply being well-known; however, it's not synonymous with "illustrious.")
- Eminent
It seems there was a bit of a mix-up with "infamous" and "notorious," which both have negative connotations. "Eminent" and "renowned" are the more appropriate synonyms that convey a positive recognition similar to "illustrious."