"STATIONARY" and "STATIONERY"
"Stationary" means not moving or not changing. "Stationery" refers to writing materials, such as paper, pens, and envelopes. Ex.: The car remained stationary at the traffic light. I need to buy some stationery for the office.
"ELICIT" and "ILLICIT"
"Elicit" means to draw out or provoke a response. "Illicit" means illegal or forbidden. Ex.: The teacher's question elicited a lively discussion. The police uncovered an illicit gambling operation.