Stiff with is a phrase that describes something that is rigid or inflexible. There are several synonyms for this phrase that can be used in different contexts, such as unyielding, immovable, unrelenting, uncompromising, and rigid. These synonyms can be used to describe physical objects, emotions, or situations, and can convey different levels of severity. For example, unyielding may be used to describe a stubborn person or a machine that cannot be adjusted, while immovable may be used to describe a boulder or an immovable object. Understanding these synonyms can help improve one's writing and communication skills by adding variety and nuance to one's vocabulary.