Saltiness; the salty taste in food or something that tastes slightly like salt. Commonly used in everyday language.
このパンにはほんのり塩気がある。
This bread has a faint saltiness.
海水は強い塩気がある。
Seawater has a strong salty taste.
塩気が強すぎて、ちょっと食べにくい。
The saltiness is too strong, so it's a bit hard to eat.