Difficult words from todays TOI editorial

I.zeitgeist(noun):
1.the general mood or quality of a particular period of history, as shown by the ideas, beliefs, etc. common at the time
2.the taste and outlook characteristic of a period or generation
Usage:
Critic told us that it had worked because it accurately captured the zeitgeist of the restless generation.(source 30th May TOI article "Love,sex,gotra..what's going on?" by Shobhaa De)

II.apostle(noun):
1.A person sent out on a special mission
2.Any of the twelve disciples sent out by Christ to teach the gospel
3.A person who strongly believes in a policy or an idea and tries to make other people believe in it:an apostle of free enterprise
Origin:Middle English, from Old English apostol and from Old French apostle, both from Late Latin apostolus, from Greek apostolos, messenger, from apostellein, to send off : apo-, apo- + stellein, to send; see stel- in Indo-European roots.
Usage:
The world millionaires had overnight converted into apostles of non violence and abandoned their T-bone steaks for goat's milk .(source TOI 30th May article "Bapu would have laughed at the Gandhi pen" by M J Akbar)

III.Crusade(noun):
1.a long and determined effort to achieve sth that you believe to be right or to stop sth that you believe to be wrong (SYN: Campaign)
Usage:
1.To lead a crusade against crime
2.Moral crusade
3.Gandhi was a great crusader-journalist (source TOI 30th May article "Bapu would have laughed at the Gandhi pen" by M J Akbar)

IV.Inveterate(adj.):
1.(of a person) always doing sth or enjoying sth, and unlikely to stop; habitual.
2.(of a bad feeling or habit) done or felt for a long time and unlikely to change; deep-rooted.
Usage
Gandhi was an Inveterate scribbler
An inveterate liar