undefinedadjective
/ˌʌn.dɪˈfaɪnd//ˌʌn.dɪˈfaɪnd/not clearly described, stated, or known:
The business is attempting to gauge how large a share of a new and largely undefined market it can seize.
not having been given a definition (= a statement explaining the meaning of something):
Certain words in the dictionary remain undefined, with only their form shown.