Comparison with Ambiguity and Generality 'Tall' is relative. A 1.8 meter pygmy is tall for a pygmy but a 1.8 meter Masai is not tall for a Masai. Although relativization disambiguates, it does not eliminate borderline cases. There are shorter pygmies who are borderline tall for a pygmy and taller Masai who are borderline tall for a Masai. The direct bearers of vagueness are a word's full disambiguations such as 'tall for a twentieth century American man'.
Words are only vague indirectly, by virtue of having a sense that is vague.
Child' is ambiguous between 'offspring' and 'immature offspring'. The latter reading of 'child' is vague because there are borderline cases of immature offspring. The contrast is further complicated by the fact that most words are also general. For instance, 'child' covers both boys and girls. Generality is obviously useful.