• aouthernness,
• zouthernness,
• xouthernness,
• douthernness,
• eouthernness,
• wouthernness,
• siuthernness,
• skuthernness,
• sluthernness,
• sputhernness,
• suthernness,
• sothernness,
• southrnness,
• southenness,
• southerness,
• southernnes,
• southrenness,
• Sotherness,
• Sootherness,
• Souterness

• southern cross,
• southern beech,
• southernwood,
• sternness,
• southern scup,
• southernism,
• southernmost,
• southern aster,
• southern lights,
• southern tai,
• southerner,
• southern porgy.

The adjective form of "southernness" is "southern".

The plural form of the word "southernness" is "southernnesses". However, this term is not commonly used, and it may be more appropriate to rephrase the sentence to avoid using the plural form.

The singular form of the word "southernness" is "southern"