To clear up	If a rash or a cold (..), it goes away
To come out in a rash/spots	A rash or spots start covering part of your body
To come out of a coma	To wake up from a coma
To come round/come to	To regain consciousness after you have fainted
To go down with sth	To become ill with sth
To pass out	To faint, to lose consciousness
To pull through	To survive and recover from a serious illness
To put sb on sth	Doctor prescribes that medicine for you to take
To put your back out	To hurt your back, often because you have tried to lift sth very heavy
To shake (sth) off	To het rid of sth
To take a tooth out	To remove a tooth
To wear off	To stop having an effect
A blinding/splitting/thumping headache	A very bad headache
A bug	An illness which is easily caught bit which is not serious and probably lasts for two days
To feel as right as rain	To feel 100% well, after having previously felt ill
A highly infectious disease	A disease that is very easily passed from one person to another
To have/suffer a nervous breakdown	To become extremely depressed and unable to cope
To have (got) poor eyesight	Not to be able to see very well and probably needing to wear glasses or contact lenses
To be hard of hearing	Not to be able to hear very well and probably needing to use a hearing aid
A stomach/tummy bug	A bug which affects the stomach
A runny nose	You have a cold and your nose is producing a lot of liquid
To be seriously-ill	To be very ill and probably in hospital as a result
Shooting pains	Sudden, sharp pains which do not last for a long time but which do repeat themselves
A sore throat	Your throat hurts that you find it difficult to swallow and sometimes even to speak
A stinking cold	A very bad cold
To have a touch of flu	To have some of the symptoms of flu (a runny nose etc) but not be so ill that you need to go to bed
To feel (a bit) under the weather/off-colour	To feel slightly ill
To have an upset stomach/to have a stomach upset	Not to be able to keep anything in your stomach because you have probably eaten or drunk sth bad
To enable sb do sth	To make it possible for sb to do sth
To encourage sb (to do sth/in sth)	To say or do things that give sb the courage or confidence to do sth
Engrossed in sth	Paying all your attention to sth (a book, film, your own thoughts etc)
To enlist (in the army/navy/airforce)	To join (the army/navy/airforce) voluntarily
To enlist the help of sb	To get sb to help
To ensure	To make sure
To entail	(Formal) to make it necessary
To entitle sb to sth	To give sb the right to have sth
To envisage	To expect
Immaterial	Not important or relevant; comes after a noun and generally follows the verb to be
Immune to sth	You cannot catch a particular illness or disease (because you have a natural resisstance to it
Immune from prosecution	Cannot be arrested or charged with a crime
Impeccable	Perfect and without faults
Impertinent	Rude and disrespectful
Impervious to sth	Not bothered or affected by sth
Implausible	Not very convincing and probably not true
Impressive	Great in size or degree or done with great skill (only used for positive things)
Imposing	Big and impressive
Imposing person	Important, with a strong character
Impromptu	Without advanced preparation or practice
Impulsive	Doing things suddenly without thinking about them carefully first