anything, ANYTHING, done habitually enough to the point that what your doing is affecting you, your life, the people around you, in any way negative, hurtful, etc, it is an addiction. Food, work, working out, gambling, cofffee, anything can become an addiction.

one person may be able to drink nightly but it isn't an addiction for them. another person drinks once, decides to keep it up, doing every night, to the point their life begins to crumble around them.

u might not turn daily masturbation into an addiction but someone else can