intellectually
In a way that uses careful thinking and reasoning.
Intellectually means using your mind, reasoning, and thinking abilities rather than your emotions or physical senses. When you engage with something intellectually, you're analyzing it, questioning it, and trying to understand it deeply through thought.
A student who finds a math puzzle intellectually satisfying enjoys the mental challenge of working through it and the process of reasoning to a solution. Scientists approach problems intellectually: they observe, form hypotheses, test ideas, and draw conclusions based on evidence and logic. When someone says a book is intellectually demanding, they mean it requires serious concentration and careful thinking to grasp its ideas.
The word can describe abilities too. Someone who is intellectually curious wants to understand how things work and why. A person who is intellectually gifted has strong reasoning and learning abilities.
Notice that intellectual work is different from physical work or emotional work. Building a treehouse requires physical effort. Comforting a sad friend requires emotional understanding. Solving a complex problem or learning a new concept requires intellectual effort because the work happens in your mind. When teachers challenge you intellectually, they're pushing you to think harder, question more, and stretch your understanding beyond what's comfortable or familiar.