hikikomori
n.— «In fact, as many as a million young men—mostly teenagers, but increasingly older men as well—suffer from what is known here as hikikomori. It’s a condition in which they seclude themselves in their rooms for weeks at a time (though the causes seem to go well beyond fear of women to traumatic experiences from the past, such as being bullied at school).» —“No sex please—we’re Japanese” by Paul Wiseman USA Today June 2, 2004. (source: Double-Tongued Dictionary)