The term 'proceed stealthily' can be summed up by the crossword solution 'CREEP, ' which is a five-letter word. To CREEP means to move slowly and quietly, often in an attempt to remain unnoticed. It is often used in situations where one is trying to avoid detection or to sneak around without being seen. This term is often used in the context of espionage or sneaking around in order to accomplish a task without being detected.