2
general::
adj. VERBS be, prove, seem | become | remain | make sth The cold weather has made it necessary to protect the crops. | consider sth, feel sth, find sth, regard sth as, see sth as, think sth Make any alterations you consider necessary. You may find it necessary to readjust the wheels from time to time. ADV. really, strictly I was determined not to stay in hospital for any longer than was strictly necessary. | absolutely | causally, logically PREP. for qualifications which are necessary for work with the under-fives PHRASES if necessary These measures will be enforced, if necessary, by the army. | as/when/where necessary We are here to give help and support when necessary.
Oxford Collocations Dictionary
3
general::
necessary
used to describe something that you need to have or do:
• Make sure you bring the necessary documents with you. • It may be necessary for you to have a small operation.
essential
very important and necessary, especially in order to be healthy, successful etc:
• Vitamins are essential for healthy growth. • The tourist industry is an essential part of the Spanish economy.
vital
extremely important and necessary, especially in order to avoid serious problems:
• A vital piece of equipment on the spacecraft had stopped operating. • It is vital that the aid is sent immediately.
compulsory
if something is compulsory, you must do it because of a rule or law:
• Maths and Science are compulsory subjects. • All new staff undergo a compulsory training course.
obligatory
if something is obligatory, you must do it because of a rule or law. Obligatory is more formal than compulsory:
• The use of seatbelts is obligatory. • Safety regulations have made it obligatory for all competitors to wear fist protectors.
mandatory
if something is mandatory, you must do it because it is the law. Mandatory is more formal than compulsory and sounds stronger:
• School attendance is mandatory. • a prisoner serving a mandatory life sentence
requisite
formal [ usually before noun ] the requisite things are the ones that you need to have in order to do something:
• The other candidates lacked the requisite skills. • the requisite evidence needed for a successful prosecution
Longman-Thesaurus