For describing physical objects:
* Flexible: This is the most general antonym, meaning capable of bending or being bent easily.
* Supple: This implies a smooth, graceful flexibility.
* Pliable: This suggests a material that can be easily molded or shaped.
* Yielding: This emphasizes giving way to pressure.
For describing a person's behavior:
* Relaxed: This indicates a calm and comfortable state.
* Easygoing: This describes someone who is agreeable and not easily upset.
* Loose: This suggests a lack of formality or restraint.
* Informal: This implies a casual and relaxed manner.
For describing a person's manner:
* Warm: This suggests friendliness and openness.
* Friendly: This implies a welcoming and approachable demeanor.
* Outgoing: This describes someone who is sociable and enjoys interacting with others.
For describing a situation or task:
* Easy: This implies that something is simple and effortless.
* Simple: This indicates that something is straightforward and not complex.
* Manageable: This suggests that something is within control and not overwhelming.
To choose the best antonym, consider the specific context in which "stiff" is used.