Stiffly means in a rigid, inflexible way, without ease or natural movement. When you move stiffly, your body feels tight and awkward, like when you've been sitting in one position too long or slept in an uncomfortable position. A robot walks stiffly because its joints don't bend smoothly like human joints do.

The word also describes behavior that feels formal or unfriendly. Someone might greet you stiffly at a party if they feel uncomfortable or don't want to talk. A character in a story might bow stiffly to show they're being polite but cold. When people interact stiffly, there's a lack of warmth or naturalness, like reading from a script instead of having a real conversation.

You might notice stiffness in writing too. A stiffly worded letter sounds overly formal and distant, like a business memo instead of a friendly note. The word captures that sense of something that should flow naturally but doesn't, whether it's movement, speech, or social interaction. After a hard soccer practice, you might walk stiffly up the stairs, with your muscles protesting every step.