I wouldn't hesitate to place "Expert" on your resume if you feel you are exceedingly competent in many, but not all, areas.
No one should be expected to have rote memorization of all language, compiler and platform features. That is just a ridiculous standard (and I know many organizations interview against it regardless). But, if you are a true master of your craft, it should only take you a day or 2 to ramp up on one of the more esoteric areas of your skillset. A master can quickly swap hats, assuming they are all more-or-less the same brand. This is a point I would try to drive home during an interview if you feel the perception is slipping. "I haven't dabbled in [XYZ framework feature] lately, but I could probably pick it back up in a few days." If I were running the interview, that's all I'd need to hear to put my mind at ease.
No one should be expected to have rote memorization of all language, compiler and platform features. That is just a ridiculous standard (and I know many organizations interview against it regardless). But, if you are a true master of your craft, it should only take you a day or 2 to ramp up on one of the more esoteric areas of your skillset. A master can quickly swap hats, assuming they are all more-or-less the same brand. This is a point I would try to drive home during an interview if you feel the perception is slipping. "I haven't dabbled in [XYZ framework feature] lately, but I could probably pick it back up in a few days." If I were running the interview, that's all I'd need to hear to put my mind at ease.