The worst. The lowest associated with the low.
In lexicons of sea language returning to 1759, the bitter-end may be the part of a cable which is round about the bits (two great timbers regularly belay cables) as soon as the ship reaches anchor. Bitter-end of this Cable, the finish which will be wound concerning the Bitts. ["The News-Readers Pocket-Book: Or, a Military Dictionary," London, 1759] See bit (n.1). So, whenever a cable is played out to the bitter-end, there is absolutely no more remaining to try out. The term began to be utilized c.1835 in non-nautical use with likely impact of bitter (adj.).
(nautical) the inboard end of a line or cable especially the end which wound around a bitt
- the final extremity (nevertheless unpleasant it may be)