Means the pilot cannot see the Ball or has lost sight of it. I think any way.
Could you define "clara". Just an unfamiliar term to me.
Yep. You can be "Clara Lineup" meaning due to glare, or some other factor, you can't see the centerline, you can be "clara ship" due to fog, but "clara" is "Clarification", meaning, you can't see a necessary visual reference to make a safe landing, and you're asking the LSO to guide you back onto course because you CAN'T do it yourself because you're missing the visual reference necessary. If you don't follow it up with what exactly you can't see, it means the ball is off the lens, so you need the LSO to guide you back down onto glide slope, and to give you warning before you have a flythrough down.