He’s doing a crossword, I’m doing the dishes. “What is that word?”, he asks, “the one that means given to incessant laughter”. “Joyful, gleeful, cheerful?” ‘No that’s not what I meant” “Mirthful, merry, enjoyment” “That’s just not it” “Well, how many letters is it?” (Now I’m getting interested) “Eight” “What does it begin with?” “I haven’t got that yet, but it does end with a N” “a N…Hmmm..Oh! I’ve got it” “What?” “I can’t remember-but its on the tip of my tongue” “That’s not helping”, he adds with sarcasm “I’m giving it all I’ve got but the word just won’t come” “Try saying it in your mind, what does it sound like?” “Aquarium” “So, its starts with an A?” “Yeah, that’s for sure” “We’ve got to find this lethologica of yours a cure!” “I’ve got! I’ve got it! Abderian is the word!”
The word "lethologica" describes the state of not being able to remember the word you want. It is a psychological disorder. The related non-pathological condition is the "tip of the tongue" phenomenon. The above is an imaginary conversation.