Which word can replace the word ill in this sentence without changing its meaning significantly?

Terry was not able to complete the project on time as he was ill.

inept

absent

indisposed

predisposed

indisposed

Terry was not able to complete the project on time as he was ill.

Can also be,

Terry was not able to complete the project on time as he was indisposed.

Indisposed is also defined as unwell, sick, slightly unwell or unable to perform.

Absent is defined as not present or out of sight and isn't congruent with ill.

Inept is defined as unskilled or without skill to perform the task, he was sick not inept.

Predisposed is liability, ill not liable nor accountable.