loopy
     adj : informal or slang terms for mentally irregular; "it used to
           drive my husband balmy" [syn: {balmy}, {barmy}, {bats},
            {batty}, {bonkers}, {buggy}, {cracked}, {crackers}, {daft},
            {dotty}, {fruity}, {haywire}, {kooky}, {kookie}, {loco},
            {loony}, {nuts}, {nutty}, {round the bend}, {around
           the bend}, {wacky}, {whacky}]
     [also: {loopiest}, {loopier}]
Source: WordNet® 2.0