讀《Usage and Abusage》

holocaust

is 'destruction by fire': do not synonymize it with disaster.  With a capital H it means the mass murder of the Jews by the Nazis.

urgent

is a strong and dignified word.  Don't cheapen it.

non-

is shamelessly and usually quite needlessly overworked by Civil Servants.  Why, e.g., non-restricted when free is available?

new and novel

The former refers to time ('it is new to me') or to state or condition ('His suit was new'); the latter to kind ('It's a novel way or method').  New is opposed to old, novel to common or well-known.

nice

is a verbal counter, a pass-partout, a word-of-all-pleasant-work; permissible - though an indication of laziness - in conversation, it is to be avoided in serious writing.

《Usage and Abusage, A Guide to Good English》，Eric Partridge著，revised by Janet Whitcut，Penguin Reference出版，第三版　1999年，ISBN　0-14--51442-2