An adverb that is widely overused by morons who are trying to sound intelligent.
To the layman, it's an alternative to but. However, the connotations of but are wholly negative, whereas however provides an Icarus from the ashes.
Use it sparingly, use it well.
She: 'I must profess I have a big butt. However, it's as shapely as the legend of bootylicious, therefore you must worship.'