fastness
buck is afraid of the man with the club
A person that is afraid of the dark has a nyctophobia
Phobiactic.
From what I understand there is no specific phobia for people who are afraid of mail. Most just call it Mail Phobia...
drug fastness is mutational forms of the original bacterial strains that appear due to sub clinical doese of the drug (under treatment)
When a dog is afraid of lighting it is called a noise phobia.
Wash fastness? Perhaps you mean color fastness? If that is the case, color fastness is the ability of fabrics to retain the dyes used to color them. Some fabrics hold dye within their fibers extremely well - like denim - while others do not (mostly synthetic or artificial non-natural fabrics) and tend to "bleed" when they are washed. The denim would therefore be more "color fast" than the other fabric.
Because they are afraid
Trypanophobics.
Insecure
Socialized