diff --git a/Mathlib/Algebra/Group/Aut.lean b/Mathlib/Algebra/Group/Aut.lean
index 512ca05c2c275..77876e7dec8e8 100644
--- a/Mathlib/Algebra/Group/Aut.lean
+++ b/Mathlib/Algebra/Group/Aut.lean
@@ -160,7 +160,7 @@ variable (A) [Add A]
 /-- The group operation on additive automorphisms is defined by `g h => AddEquiv.trans h g`.
 This means that multiplication agrees with composition, `(g*h)(x) = g (h x)`.
 -/
-instance instGroup : Group (AddAut A) where
+instance : Group (AddAut A) where
   mul g h := AddEquiv.trans h g
   one := AddEquiv.refl _
   inv := AddEquiv.symm