We don't have synonyms for anti-national yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are antinational and antirational.
(adj) :
Alternative spelling of antinational. [(politics) Opposed to one's own nation; unpatriotic.]
(n) :
Alternative spelling of antinational. [(Indian politics, Hindutva, derogatory, accusatory) One who is opposed to India, usually suggesting pro-Pakistan or leftist associations, hostility against the Hindu religion, or opposition to Hindu nationalism.]
(adj) :
Alternative spelling of antinational. [(politics) Opposed to one's own nation; unpatriotic.]
(n) :
Alternative spelling of antinational. [(Indian politics, Hindutva, derogatory, accusatory) One who is opposed to India, usually suggesting pro-Pakistan or leftist associations, hostility against the Hindu religion, or opposition to Hindu nationalism.]