Juˈdas-coloured adjective

(of hair) red (Judas traditionally being red-haired)

Judas hole or Judas window noun

(also without caps) a spyhole in a door, etc

Judas kiss noun

Any act of treachery under the guise of kindness (from the Bible, Matthew 26.48–49)

Judas tree noun

1. A tree (genus Cercis) of the Caesalpinia family, with rose-coloured flowers that appear before the leaves (Judas being traditionally believed to have hanged himself on one)
2. Also the elder (for the same reason)