tenuous

反对意见是脆弱的，缺乏坚实支持。

The objection is ___tenuous, lacking firm support.

这一证据站不住脚，既薄弱又缺乏实质。

The evidence is ___tenuous, weak and insubstantial.

蜘蛛丝看起来非常纤细脆弱。

The spider's silk appears extremely ___tenuous and fragile.