IPA: /ˈsɪk.lɪ.nəs/
KK: /ˈsɪk.lɪ.nəs/
The condition of being weak or unwell, often due to ongoing health problems.
His sickliness made it difficult for him to participate in sports.
Sickliness → It is formed from "sick" (from Old English "sēoc", meaning ill or unwell) and "-ness" (meaning the state or condition of). The word "sickliness" refers to the state of being sick or ill.
Think of the word 'sick' to remember that 'sickliness' means the condition of being unwell.