WordNet sense 1 (possibly accepting or permitting):

open, subject, subject

WordNet sense 2 ((often followed by `of' or `to') yielding readily to or capable of):

susceptible

WordNet sense 3 (properly or sufficiently qualified or capable or efficient):

competent

WordNet sense 4 (having inherent physical or mental ability or capacity):

able

WordNet sense 5 (having the requisite qualities for):

adequate to, up to, equal to

WordNet sense 6 ((sometimes followed by `to') meeting the requirements especially of a task):

adequate