Intermediate (B1)
IPA: /ˌɪn.kəmˈpæt.ə.bəl/
KK: /ɪnˈkɒmpətəbl/
Definition
Not able to exist or work together without conflict or problems.
Example
Their ideas were incompatible, leading to a heated debate.
Conversation

I heard you and Mark had a falling out.

Yeah, we realized our views are really incompatible on a lot of things.

That's tough; it's hard when friends can't see eye to eye.

True, sometimes it's just better to go separate ways.
Synonyms & Antonyms
Synonyms
conflicting
antagonistic
discordant
Antonyms
compatible
harmonious
congruent
Definition
A person or thing that cannot exist or work together with another due to differences or conflicts.
Example
The two software programs are known to be incompatibles, causing errors when used together.
Conversation

I heard you and Jake had a rough time working together.

Yeah, we just have such different styles; we're basically incompatible.

That’s too bad, I thought you two would make a good team.
Root Explanation
Incompatible → It is formed from "in-" (meaning not) and "compatibilis" (from Latin, meaning able to exist together). The word "incompatible" means not able to exist or work together harmoniously.
Memory Tip
Think of 'not' ('in-') being able to 'exist together' ('compatibilis') — that's why incompatible means things that cannot work together.
Visually Confused Words
uncompatible
compatible
compactible
impatible
uncompatibly
impartible
compatibly
uncompaniable