Princeton's WordNet

1. ten, 10, X, tenner, decade(noun)

   the cardinal number that is the sum of nine and one; the base of the decimal system

   Synonyms:
   decade, cristal, ten-spot, ten, go, disco biscuit, ecstasy, ex, decennium, tenner, decennary, hug drug, ten dollar bill

   Antonyms:
   ordinal

2. X, x, ex(noun)

   the 24th letter of the Roman alphabet

   Synonyms:
   decade, cristal, x, ex-wife, ten, go, disco biscuit, ecstasy, ex, tenner, hug drug, ex-husband

   Antonyms:
   ordinal

3. Adam, ecstasy, XTC, go, disco biscuit, cristal, X, hug drug(adj)

   street names for methylenedioxymethamphetamine

   Synonyms:
   turn, hug drug, disco biscuit, ten, go game, ex, fling, transport, tour, rapture, crack, tenner, whirl, ecstasy, exaltation, decade, pass, spell, go, raptus, offer, cristal

   Antonyms:
   ordinal

4. ten, 10, x(adj)

   being one more than nine

   Synonyms:
   x, ten

   Antonyms:
   ordinal