Anti vs Pro
Antibiotics – Probiotics
antihistamine – Prohistamine
antidepressant – prodepressant
Antidote – prodote
Antibacterial – probacterial
Anticipate – procipate
Antiseptic – proseptic
Antimacassar – promacassar
Antipasto – propasto
Antipathy – propathy
Antigen – progen
Antidisestablishmentarianism – prodisestablishmentarianism
Antique – proque
Antitheses – protheses
Pro vs Anti
Probably – antibably
Probation – antibation
Probe – antibe
Problem – antiblem
Procedure – anticedure
Proceed – anticeed
Profession – antifession
Profane – antifane
Profile – antifile
Profit – antifit
Prohibit – anithibit
Protect – antitect
Profound – anitfound
Project – antiject
This is what happens when you have too much time on your hands.
Thought For Food 
LMFAO @ Progress being opposite of Congress!!!!!!! You Da MAN!
LOL…great idea Eric! Protest – contest….Profile – confile…produce – conduce. LOL
You could do a Part 2 of this idea using “Con” instead of “Anti” (Like “Progress” and “Congress” – LOL!)