The phrase "cannot be defined exactly" is correct and can be used in written English.
For example, one might say: "The exact definition of the word 'irony' cannot be defined exactly."
One senior executive maintains that innovation simply cannot be defined exactly, but that "like pornography I know it when I see it".The wrong measureSpecial report Something new under the sun Revving up Can dinosaurs dance?
Temperate zones for horticulture cannot be defined exactly by lines of latitude or longitude but are usually regarded as including those areas where frost in winter occurs, even though rarely.
Now, in order to get the paradox, one has to prove that there exists a unique number N in (0, 1), satisfying the condition given by Richard (see 2.5 above), but this condition, and hence N itself, depends on Val, which is possibly obscure and cannot be defined exactly according to the rules of mathematics (p. 352, p. 358).
"Our community cannot be defined by one group.
Femininity cannot be defined by cup size.
Being successful cannot be defined by society.
Yet it cannot be defined in singularity.
Reliable cannot be defined as "able to be relied".
And the real self cannot be defined in any way.
My Jersey Shore cannot be defined by any reality show.
It cannot be defined by one's actions.
