I have just been looking at this old thread. There are a surprising number of other "kangaroo words". Here is another containing both a synonym and an antonym:

fabrication – fiction [synonym]
fabrication – fact [antonym]

Other kangaroo words I have come up with:

ungainly – ugly
cornet – cone
gigantic – giant
traitor – rat
indolent – idle
stellar – star
discourteous – curt
median – mean
regulate – rule
education – Eton
routine – rote
enthusiast – nut
eliminate – mate (in chess)
Wordsmith – wit, worth

absorbing – boring [antonym]