Continuing the look at synonyms through the eyes of the etymologist, this time it is the letter M and mad. There are three usages for 'mad': as an adjective, as in 'insane'; as an adverb, as in 'oddly'; and as a verb, as in 'anger'. In all three cases the original sense seems to have been the adjective, this coming to English through the Germanic route and while the Old Saxon word gimed meant 'foolish', the Gothic version of gamaiths was used to mean 'wounded, crippled', and the Old Norse meitha 'to hurt, maim'. All these are derived from the Proto-Indo-European mei 'to change, move', a root which has also given us the word 'migrate'.
Insane is clearly derived from 'sane', itself from the Latin sanus 'sound, healthy', and from Proto-Indo-European seh 'to tie' and later used to mean 'to put in place or order'.
Derange is from the French desrengier 'throw into disorder' and thus the opposite of the reng 'line, row', related to Proto-Germanic hringaz 'circle, ring, curved', and back to Proto-Indo-European sker 'to turn, bend'.
Demented is from an obsolete verb dement 'to drive mad'. Here the first element is the negative 'de-', with the Proto-Indo-European men 'to think'.
Crazy is from the original 'craze', itself a Germanic word meaning 'to shatter, crush, break in pieces'. It seems likely to have come to English from Old Norse kraza 'shatter'.
Ardent is from the Old French ardant 'burning, hot, zealous'. Here the word came from Latin ardere 'to burn' and Proto-Indo-European as 'to burn' or 'glow'.
Zealous comes from 'zeal', itself from Old French zel and Latin zelus and Greek zelos all meaning 'ardour, rivalry, emulation'. All these can be traced to Proto-Indo-European ya 'to seek, request, desire'.
Fervent is another coming to English from Old French, and ultimately from Proto-Indo-European bhreu 'to boil, bubble, effervesce, burn'.
Eager, also from Old French where aigre 'sour, acid, harsh, bitter, lively, eager, active, forceful', came from Latin acrus and ultimately from Proto-Indo-European ak 'be sharp, rise to a point, pierce'.
Angry is from 'anger' and came to English from Old Norse angra 'hostile, distress, suffering, agony'. It can be traced back further to Proto-Germanic angaz and to Proto-Indo-European angh 'tight, painfully constricted, painful'.
Irate, or 'ire', comes from Old French ire and Latin ira 'anger, wrath, passion'. Ultimately from Proto-Indo-European eis, this word has produced innumerable words indicating passion, such as the Greek hieros 'filled with the divine' and oistros 'causing madness'; Sanskrit esati 'drives on' and yasati 'boils'; Avestan aesma 'anger'; and Lithuanian aistra 'violent passion'.
'Mad' appears in several phrases, including 'like mad', which was first recorded in 1650; 'mad as a March hare' from the 1520s; 'mad as a hatter' from 1829; one could not be a 'mad scientist' before 1891; and as 'mad as a wet hen' since `1823'.