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.
- cross-fertilization
- cross-fertilize
- cross-file
- cross-filer
- crossfire
- cross-grained
- cross hair
- crosshair
- crosshatch
- cross-hatching
- crosshead
- cross-index
- crossing
- crossing over
- crossing-over
- cross-legged
- cross-link
- crossly
- cross matching
- cross mind
- cross multiplication
- cross-multiply
- cross-national
- crossness
- cross (one's) mind