Strictly means following rules, standards, or definitions in an exact and precise way, without any exceptions or flexibility. When a teacher grades strictly, they follow the rubric precisely and don't give extra credit for effort. When parents enforce a bedtime strictly, 8:00 means 8:00, not 8:15.

The word often appears in phrases like strictly forbidden, which means absolutely not allowed under any circumstances. A sign reading “strictly no running” in a pool area means the rule applies to everyone, always. When someone says they're strictly vegetarian, they never eat meat.

Strictly speaking is a useful phrase that means “if we're being completely accurate.” You might say, “Strictly speaking, tomatoes are fruits, not vegetables,” because you're pointing out the technical, scientific definition rather than how people usually think about tomatoes. This phrase signals that you're about to get precise about something.

The word can also mean “only” or “purely,” as in “This meeting is strictly business,” meaning no joking around or personal conversation, just work.