In regards to yesterday's post on the same topic, the entry at
oed_word_of_the_day_feed is morigerous, which I will never ever have a chance to use in casual conversation, but I'm glad to know it already.
By contrast,
merriamwebster_feed gives us penultimate and
wordsmithdaily_feed has humdinger, so I think that a fair and unbiased comparison of the three will clearly show that the OED's feed is the obvious winner. Nothing against penultimate or humdinger, but I can use those in conversation even with small children and didn't need them defined for me today.
* I promise
By contrast,
* I promise