diff --git a/src/types/objects.ts b/src/types/objects.ts
index 67a4e42..bfdfdf0 100644
--- a/src/types/objects.ts
+++ b/src/types/objects.ts
@@ -1,4 +1,3 @@
-import { Diff } from './strings';
 import { False, True } from './conditionals';
 import { AnyFunc } from './functions';
 
@@ -127,7 +126,7 @@ export type UnionizeProperties<T extends object> = T[Keys<T>];
  * @param K the union of keys to remove from `T`
  * @returns `T` with the keys `K` removed
  */
-export type Omit<T extends object, K extends Keys<T>> = Pick<T, Diff<Keys<T>, K>>;
+export type Omit<T extends object, K extends Keys<T>> = Pick<T, Exclude<Keys<T>, K>>;
 /**
  * Returns only the shared properties between two objects.
  * All shared properties must be the same type.
diff --git a/src/types/strings.ts b/src/types/strings.ts
index 8c58e4d..79469ba 100644
--- a/src/types/strings.ts
+++ b/src/types/strings.ts
@@ -1,15 +1,12 @@
 import { True, False, And } from './conditionals';
 import { IsNever } from './predicates';
 
-// TODO: this is here only for backwards compatibility
-export type Diff<T, U> = Exclude<T, U>;
-
-export type DropString<T extends string, U extends T> = Diff<T, U>;
+export type DropString<T extends string, U extends T> = Exclude<T, U>;
 
 export type StringEqual<T extends string, U extends string> =
     And<
-        IsNever<Diff<T, U>>,
-        IsNever<Diff<U, T>>
+        IsNever<Exclude<T, U>>,
+        IsNever<Exclude<U, T>>
     >;
 
 export type UnionContains<T, U> = U extends T ? True : False;
diff --git a/test/strings/Diff.test.ts b/test/strings/Diff.test.ts
deleted file mode 100644
index 1c729aa..0000000
--- a/test/strings/Diff.test.ts
+++ /dev/null
@@ -1,15 +0,0 @@
-import test from 'ava';
-import { assert } from '../helpers/assert';
-
-import { Diff } from '../../src';
-
-test('Can get difference between unions of strings', t => {
-    type a = 'hi' | 'there';
-    type b = 'hi' | 'my' | 'friend';
-
-    type gotA = Diff<a, b>;
-    type gotB = Diff<b, a>;
-
-    assert<gotA, 'there'>(t);
-    assert<gotB, 'my' | 'friend'>(t);
-});