That's long :( Wishing you courage for the next 3 months :)

XX - XY

Genetic coding :p

Yummy - yucky

And I was thinking Xenophobia - Xenophilia :)

Zip-Zippless.

Synonyms:

Alert- Aware
Blast-Blow

Crib - Cheat
Dang - Drat
End - Eliminate

Fault - failure

Good-Great
Humurous-Hilarious
Inspector-Investigator

Great - Grand
Heightened - Honed

Gah, too slow

Oh I didn't even think anyone else was here. Well you can have the next one then Synnen.

Indisputable - indeniable

Jerk-Jackass
Kingsmen-Knight

Ingenious-Intelligent
Joke-jape

Crap, I'm too late! Lol

Love-lust

Marvellous - magnificent
Near - neigh

Odd - Off
Punctual - Prompt
Quake - Quiver

Rowdy - rambunctious
Stable - steady
Testament - testimony

Ugly - Unattractive
Vale - Valley
Wring - Wrench

X anyone or forfit?

I've wracked my brain and cannot come up with one for X.