become more intense; "The debate intensified"; "His dislike for raw fish only deepened in Japan"
make more intense, stronger, or more marked; "The efforts were intensified", "Her rudeness intensified his dislike for her"; "Pot smokers claim it heightens their awareness"; "This event only deepened my convictions"
make the chemically affected part of (a negative) denser or more opaque in order produce a stronger contrast between light and dark
based on custom rather than documentation; "an unwritten law"; "rites...so ancient that they well might have had their unwritten origins in Aurignacian times"- J.L.T.C.Spence