“sick”

Suffering from a disease or ailment that causes persistent distress.

“She lay afflicted with fever for three days, unable to lift her head from the pillow.”

Best for: Works well in formal writing or when emphasizing the weight of suffering.

Mildly unwell or temporarily unfit for normal activity.

“The director sent word that he was indisposed and would not be attending the board meeting.”

Best for: Polite and understated; perfect for professional or formal social contexts.

Weakened in body or health, often with a sense of lasting fragility.

“After the harsh winter, he returned looking gaunt and infirm, a shadow of his former self.”

Best for: Best for literary or historical settings; implies ongoing physical weakness.

Of or relating to disease; in a diseased or pathological state.

“The physician noted a morbid pallor spreading across the patient's skin.”

Best for: Clinical and literary contexts; carries a darkly serious or foreboding tone.

Looking pale, wan, and sickly in appearance.

“You look positively peaked — when did you last sleep or eat a proper meal?”

Best for: Conversational but vivid; common in British and regional American English.

Chronically poor in health and excessively preoccupied with illness.

“The valetudinary count rarely left his estate, convinced each draft would be his undoing.”

Best for: Extremely rare; ideal for period fiction or showing off precise vocabulary.