Another possible research topic (probably already investigated):
“Pretty-ness in Shakespeare.”
Why is the king calling Ophelia “pretty lady”? Usually she’s called “Fair” and “fairness” appears a whole lot more in Shakespeare than “pretty.” Are there distinctions between “pretty,” “fair” and “beautiful” at this time?
“Pretty” has a kind of diminutive quality. Maria in West Side Story feels pretty – not beautiful. Pretty has a youthful quality. Young girls are pretty. Women are beautiful. Men are never pretty in Shakespeare. But I suspect Adonis (at least) is beautiful. There is male and female beauty – but men who are pretty are feminine – so in a sense pretty men might as well be women as far as these distinctions go.
It does make me wonder if Claudius is speaking to Ophelia like a child.