suffixes
forget
forgetful
possible
impossible
free
freedom
agree
disagree
happy
happiness
create
creation
able
unable
train
trainee
regular
irregular
friend
friendship
govern
government
cook
overcook
write
writer
legal
illegal
express
expression
innovate
innovation
grade
downgrade
king
kingdom
motivate
demotivate
complex
complexion
complicate
complication
pleasure
displeasure
post
postage
active
interactive
equal
equality