Diffuse is defined in the following was: “(1) To spread out. (2) To move freely throughout a large area. (3) To exist or be known throughout an area. (4) To cause (light) to be soft and spread out. (5) Being at once verbose and ill-organized.”

Defuse is defined as: “(1) To remove the fuse from (as a mine or bomb). (2) To make less harmful, potent, or tense.”

Briefs:
Option #1: diffuse= DIF/FAO*US
Option #2: diffuse= DA/FAOUS

Option #1: defuse= DE/FAOUS
Option #2: defuse= DPAOUS