Explain/define
Synonym
Antonym
Collocation
100

well up

fill up

100

contention

disagreement, argument, debate

100

erratic 

consistent, regular, stable

100

benign

tumour, smile, humour, environment, conclusion, method, association, report

200

brownie points

approval for something helpful you have done

200

hands down

definitely, for sure

200

up to scratch

below standard, unacceptable

200

up to scratch

to be / come up to scratch

300

bury yourself in

to give all your attention to something

300
predicate on

to base on, establish on, rely on, build on

300

imperceptible 

noticeable, obvious, visible

300

remit

narrow/wide

to have a / no remit to do sth

be/fall outside sb's remit 

be/fall within/under sb's remit

400

trickle down to

to start at the top of a system, organization, etc. and spread to all of it

400

mug up on sth

cram for, grind, study hard

400

prerequisite

extra, luxury, nonessential, nonnecessity

400

reap

the benefits, rewards, fruits of your labour, harvest

500

burn the candle at both ends

to work or do other things from early in the morning until late at night and so get very little rest

500

negligible

trivial, insignificant, unimportant, slight, hardly noticeable

500

indispensable 

unnecessary, non-essential, superfluous

500

nimble

mind, fingers, feet, hands, person

nimble handling of the [issue, dilemma, problem, situation]