IPA: /ˈsɔːftər/
KK: /ˈsɔftər/
Having a texture or quality that is less firm or hard than something else; gentle or mild in nature.
The pillow is much softer than the old one.
Softer → It is formed from "soft" (from Old English *softe*, meaning not hard or firm) and "-er" (meaning more). The word "softer" means more soft or having a greater degree of softness.
Think of something that is 'not hard' ('soft') and remember that 'softer' means it has more of that quality.