ill
瘏 centers on being ill or sick. The single given meaning is straightforward, with no additional distinct senses to connect.
瘏 combines the sickness radical 疒 with 者, which likely provides the sound. The character is rare, and its exact historical development is uncertain.
The sickness enclosure 疒 wraps around 者, like a person (者) being confined by illness. Picture someone bedridden and ill inside the sickness shell.
For ト, imagine a toe (ト) that is ill and swollen, making it hard to walk. The sore toe cues ト while the sickness enclosure shows the illness.