Difference between strength and stiff/rigid

Strength --> ability to absord the load/force given without breaking or failure

Stiff/rigid --> ability to maintain the original shape (or with less deformation) when load/force applied to it

Example:
Cookies --> Strength: Low, Stiffness: High
Jelly --> Strength: Low, Stiffness: Low
Baby's milk bottle --> Strength: High, Stiffness: High
Nylon cable tight --> Strength: High, Stiffness: Low

Thanks to University of Liverpool for their very useful website in this matter :)
Ref: www.matter.org.uk/schools/content/YoungModulus/introduction.html