As much as everyone was making fun of Bidens loss of function (which… Biden always tripped up over words. He always was a bad speaker)… Trumps wit has visibly declined over the recent years.
It’s possible that Trump just can’t come up with a reasonable insult due to his advanced age. IMO, Trumps signs of aging are worse than even Bidens.
Crooked was Hilary Clintons nickname. So same problem as Lying: it is proof of Trumps small vocabulary if he recycles an insult.