Tra từ former - Từ điển Oxford Advanced Learner 8th

for·mer [former formers] BrE [ˈfɔːmə(r)] NAmE [ˈfɔːrmər] adjective only before noun
1. that used to exist in earlier times
•in former times
•the countries of the former Soviet Union
• This beautiful old building has been restored to its former glory.
2. that used to have a particular position or status in the past
•the former world champion
•my former boss/colleague/wife
3. the former…used to refer to the first of two things or people mentioned
• The former option would be much more sensible.
compare ↑latter
4. the formerpronoun the first of two things or people mentioned
• He had to choose between giving up his job and giving up his principles. He chose the former.
compare ↑latter
Idiom: ↑a ghost of your former self

Word Origin:
Middle English: from Old English forma ‘first’ + ↑-er.

Thesaurus:
former adj.
1. only before noun
•The palace has been restored to its former glory.
past • • old • • previous • |formal prior •
Opp: present, Opp: future
Former, past or old? Use former or past to talk about times gone by; use old to talk about things from your own life: my old school/colleagues/friends. Former can also describe sth that has changed: the former Yugoslav republic. A former friend is sb who is no longer your friend; an old friend is sb you have known for a long time.
2. only before noun
•She's the former world champion.
ex- • • old • • then •
Opp: current, Opp: future
sb's former/ex-/old/then partner/boyfriend/girlfriend
sb's former/ex-/then husband/wife
a/an former/ex-/old lover/colleague/member
a/an former/old friend/ally/enemy
Former or ex-? Former has a wider range of collocates. Ex- is less formal and preferred in spoken English.

Example Bank:
•It is one of the countries of the former Soviet Union.
•She's the former world champion.
•The historic quarter of the city has been restored to its former glory.
•This fine ruin was, in former times, a royal castle.