What is the meaning of flag off?

Answer 1

The terms Flag off and Flag on are frequently used by writers, sometimes with different meanings, though major dictionaries have not considered them fit enough for inclusion.

Fowler is silent on this. Merriam-Webster's Advanced dictionary does not explain these phrasal verbs. American Heritage dictionary has no entry for this.

To make it more complicated, there is a word Flagon referring to a container for liquids.

As a verb, Flag stands for giving signal. You flag a taxi to stop; you flag a waiter to take your orders; you flag a football player for giving a penalty.

We do come across 'Flag on' and 'Flag off' with the meaning 'signal for a start or beginning'.

Even though the word 'Off' often stands for a negative meaning, 'Flag off' is used to mean that somebody gave the orders to start something like a 'race'.

I think that the writers should use these two phrasal verbs sensibly; 'Flag on' should stand for 'signal a start or beginning' and 'Flag off' should stand for 'signal an end or conclusion. This is logical and is by and large followed by responsible writers. Any deviation from this should be treated as a mistake.