agerasia
n. youthful appearance in an old person

Also:

neanimorphism
n. the quality of looking younger than one’s age

psaphonic
n. planning one’s rise to wealth and fame

exsibilation
n. the action of hissing off the stage

opsimath
n. one who studies late in life

phobophobia
n. fear of phobias

eccedentesiast
n. one who fakes a smile

adoxography
n. fine writing on a trivial subject

fysigunkus
n. one who lacks curiosity

gamomania
n. an urge to make extravagant wedding proposals

engastration
n. the act of stuffing one bird into another