Hamlet
RALPH: The word pregnant was used earlier, in Hamlet's conversation with Polonius. Polonius uses it to refer to Hamlet's strange replies to his questions — and there, we saw that Shakespeare used it figuratively to mean that Hamlet's words were full of hidden meaning.
SARAH: Here, when Hamlet says he is unpregnant of his cause, he means he's unresourceful, or unimaginative.
RALPH: In other words, he is not full of, or pregnant with, motivation or resources. But Sarah, is Shakespeare explicitly echoing his earlier use of the word here? Are we supposed to associate Hamlet's pregnant replies with his being unpregnant of his cause?
SARAH: It's possible, Ralph — after all, in this monologue, Hamlet is contrasting his words to his actions. So it's appropriate that his replies are pregnant, or full of meaning, but this doesn't help him be full of motivation or the drive to act and seek revenge.