As soon as I read the title of this thread, I assumed that 'hos' referred to horse! I don't know about terminology in the USA or anywhere else for that matter but in England, if you're on a 'nappy headed horse', then you've got equine attitude problems. Nappy, in this case, has nothing to do with infant attire, more with a horse that has decided that it doesn't want to be where you want it to be, in fact it would rather be back in its paddock eating grass. When Cysgod, my 16h gelding gets his 'nappy' head on him, my usual calm and collected aids turn into a tirade of "do as you're BL**DY WELL TOLD, YOU STUPID B*****D", or something to that effect.