Is there a word for not being able to find the right word?

I was trying to right today and kept coming up with lots of words to describe what I was trying to say but had this urge to find one word to succinctly state what was taking a lot of words to express. I'm not joking: I have roughly four or five descriptions beginning with 'is there a word for...?'

I suggest the proper term is "logophasia."

this is such a common thing that there seem to be several possibilities. the one I remember(!) is lethologica.

By jove, I think we've got it!

Lethologica: the inability to remember a word or put your finger on the right word.

Write on...