• colod sore,
• cold sores,
• col sore,
• cold sore,
• kold sore,
• coldpsore,
• cold0-sore,
• cold-0sore,
• coldp-sore,
• cold-psore,
• cold--sore,
• coldmsore,
• coaled-sore,
• cold-soar,
• cold-sewre,
• cold-sowre,
• Col-dore,
• Colldsore,
• Koldsore

The adjective form of "cold-sore" is "cold-sore". In this case, the word does not change when used as an adjective.

The plural form of "cold-sore" is "cold-sores".

The singular form of "cold-sore" is still "cold-sore". It does not change in its singular form.