did an LLM get involved in your dictionary somehow? (why are four of these six definitions very minor rephrasings of each other?)

Fwiw, the American Heritage Dictionary has only one definition; the other two are in wiktionary (which has citations for both).

Certain Russian leaders defenstrate people who buck the status quo

Certain computer users defenstrate Windows slop from their lives (Penguins)

Why is it oddly specific? “Fenestre” is window in latin languages, “de-” prefix is negation. Microsoft Windows is “Micro-mollis Fenestrae” in latin, but there is a even a latin language article about it on wikipedia: https://la.wikipedia.org/wiki/Microsoft_Windows