Use 'antithetical' to stress strong or extreme opposition between ideas, actions, or traits. Their peaceful approach was antithetical to the aggressive negotiations.
Pro Tip 2/3
Not Mild Contrast
'Antithetical' suggests more than just a slight difference; it emphasizes complete contrast. Using violence to promote peace is an antithetical concept.
Pro Tip 3/3
Context Sensitive
'Antithetical' can be nuanced based on context, sometimes indicating a complementary rather than hostile relation. Silence can be antithetical to chaos, yet both serve a purpose in the natural world.