puer·il·ism 
(pyrə-lĭz′əm, pwĕrə-, pyər-ə-)
(pyrə-lĭz′əm, pwĕrə-, pyər-ə-)n.
Childish behavior in an adult, especially as a symptom of mental illness.
- Ferdinand Julius
- Ferdinand Marie.
- Ferdinand Marie de
- "Ferdinand the Catholic."
- "Ferdinand the Great."
- Ferdinand V
- Ferdinand von
- Ferdowsi
- Ferdowsi
- fere
- feretory
- Fergana
- Ferghana
- feria
- ferial
- ferine
- ferity
- Fermat
- fermata
- Fermat's last theorem
- ferment
- fermentability
- fermentable
- fermentation
- fermentative