A ‣ Informal expressions relating to time 
We only meet once in a blue moon. [very infrequently]
He’s spent all his born days in the village. [all his life]
I’ll be with you in a mo / in a sec / in a tick / in less than no time / in a jiffy. [very soon] (mo and sec are short for ‘moment’ and ‘second’)
Clive’s been working here for donkey’s years / since the year dot. [for a long time]
We can talk about this till the cows come home, but I’m not going to change my mind. [for ever]
Are you sure she gave you the book for keeps / for good? [to keep for ever]
She turned up just in the nick of time – she very nearly missed the train. [only just in time]
He was a famous athlete but now he’s over the hill / past it. [too old]
She was a child film star but was already a has-been by the age of 20. [person who is no longer famous]
Sue did her homework in a flash / at a rate of knots. [very quickly]
B ‣ Adjectives relating to the passing of time 
adjective | meaning | common collocations |
fleeting | brief or quick | glimpse, visit, smile, moment, appearance |
lengthy | continuing for a long time | process, investigation, discussions, negotiations, delays |
transient | lasting for only a short time; formal | effect, population, feeling, pleasure |
persistent | lasting for a long time or hard to stop or get rid of | cough, problems, rumour, smell, accusations, critic, offender, failure, gossip |
inexorable | continuing without hope of being stopped; formal | rise, slide, decline, pressure, advance of time |
incipient | just beginning; formal | panic, rage, rebellion, stages, wrinkles, dementia |
protracted | lasting for a long time or made to last longer; formal | negotiations, discussions, argument |
lingering | taking a long time to leave or disappear | perfume, kiss, smile |
C ‣ Other useful time words 
Terrorists carried out simultaneous attacks on three places in the capital. [happening at the same time]
Schools were closed for the duration of the President’s visit. [amount of time that it lasted]
We shouldn’t prolong the meeting; we’ve already discussed the matter for an hour. [make it last longer]
I’m sorry, I can’t change the date at such short notice. [just a short time before it is due to happen]
The teacher repeatedly warned the student that she would fail her exam. [many times]