diff --git a/lib/rules/function-no-unknown/__tests__/index.js b/lib/rules/function-no-unknown/__tests__/index.js
index 0c2ea6251c..3dab33c82e 100644
--- a/lib/rules/function-no-unknown/__tests__/index.js
+++ b/lib/rules/function-no-unknown/__tests__/index.js
@@ -27,18 +27,24 @@ testRule({
 			message: messages.rejected('unknown'),
 			line: 1,
 			column: 16,
+			endLine: 1,
+			endColumn: 23,
 		},
 		{
 			code: 'a { transform: UNKNOWN(4); }',
 			message: messages.rejected('UNKNOWN'),
 			line: 1,
 			column: 16,
+			endLine: 1,
+			endColumn: 23,
 		},
 		{
 			code: 'a { width: calc(10% * unknown(1)); }',
 			message: messages.rejected('unknown'),
 			line: 1,
 			column: 23,
+			endLine: 1,
+			endColumn: 30,
 		},
 	],
 });
diff --git a/lib/rules/function-no-unknown/index.js b/lib/rules/function-no-unknown/index.js
index 39ea970ef8..87e89f7dce 100644
--- a/lib/rules/function-no-unknown/index.js
+++ b/lib/rules/function-no-unknown/index.js
@@ -49,6 +49,8 @@ const rule = (primary, secondaryOptions) => {
 			const { value } = decl;
 
 			valueParser(value).walk((node) => {
+				const name = node.value;
+
 				if (node.type !== 'function') {
 					return;
 				}
@@ -57,24 +59,25 @@ const rule = (primary, secondaryOptions) => {
 					return;
 				}
 
-				if (isCustomFunction(node.value)) {
+				if (isCustomFunction(name)) {
 					return;
 				}
 
-				if (optionsMatches(secondaryOptions, 'ignoreFunctions', node.value)) {
+				if (optionsMatches(secondaryOptions, 'ignoreFunctions', name)) {
 					return;
 				}
 
-				if (functionsList.includes(node.value.toLowerCase())) {
+				if (functionsList.includes(name.toLowerCase())) {
 					return;
 				}
 
 				report({
-					message: messages.rejected(node.value),
+					message: messages.rejected(name),
 					node: decl,
 					index: declarationValueIndex(decl) + node.sourceIndex,
 					result,
 					ruleName,
+					word: name,
 				});
 			});
 		});