The best replacement for fragile is frail.

The best alternatives to fragile are rated as following:
★★★★★  frail
★★★  brittle
★★★  fragile
★★  agile
★  close to the edge
★  downward spiral

Your alternative for fragile is not listed? Suggest!
Speaking about fragile, one probably shouldn't forget about sting and yoyo ma.

Other search terms related to fragile and their ratings are:
★★★★★ sting and yoyo ma
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fragile
frail
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