The English language adjectives Fragile, Brittle, Delicate and Vulnerable have related meanings, but they are all different, as I shall explain, using British English examples.
Fragile describes an object that will break if handled without care. This can be an inherent feature of the object, or something which an object acquires through age.
"Our wine glasses are fragile and must be packed carefully when we move house."
"The pages of this ancient book are extremely fragile."
Sometimes we describe people as being fragile, which refers to someone who can easily become distressed.
"For months after I was attacked in the street, I was feeling very fragile."
Also, fragile is used to describe someone with a hangover.
"I'm feeling pretty fragile after last night!"
Brittle describes something that is hard and will easily break if pressure is applied to it, for example if it is dropped. When something brittle breaks, it will normally become lots of smaller pieces. Only hard things can be brittle.
"The ancient teacup is extremely brittle."
"The doctor told me my grandmother's bones are quite brittle now."
Delicate means an object that has lots of fine detail, or one that can be ruined if handled incorrectly. Delicate doesn't say anything about whether it will break or not. Delicate things need to be handled with care and will be ruined if they are not.
"My lace dress is very delicate so I always wash it by hand."
"In the frost, this spider's web looks so beautiful and delicate."
Delicate is also used to describe something that must be handled with great care, even if it is not a physical object.
"The two Governments were locked in delicate negotiations."
Vulnerable means something is in a position where it could come to harm. The word is often (but not always) used to describe a person.
"Homeless people are vulnerable to being attacked on the streets."
"I feel quite vulnerable walking home alone at night."
"These small islands are vulnerable to flooding."
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