Give way is a road sign.  Traffic approaching it has to allow other traffic priority.  If something gives way it may collapse.

A giveaway used to be some evidence.  If someone had knowledge specific to a time or place, that could be a giveaway (that they were there).  Nowadays a giveaway is more likely to be a free gift or to use the modern word a freebieA person in hiding may give themselves away by sneezing, for example.

Give in means much the same as give up.  If someone is pestered for long enough they may give in to the demands being made.  They give up their opposition.  Give up may also mean ‘go without’ as in, “What are you giving up for Lent?” or ‘surrender’.

Give over is a Northern English expression meaning stop.

When an irresistible force meets an immovable object something’s got to give.

Is this an oxymoron?

A landslide defeat occurs when a large number of voters apparently change sides.  The opposing party must then win by a landslide.

A celebration is called for when something particularly good has happened or is happening.

In Lancashire they had an expression: They’ll be having a fatter do and a fire upstairs.
Under normal circumstances a fire was lit in only one room downstairs, although other rooms had fireplaces (hearths).  Fatter perhaps refers to richer food or more of it than usual.

Dressed to the nines describes someone who has made a real effort with their appearance.

A pretend birthday is one celebrated on a different date, perhaps to accommodate guests, who are unavailable on the actual birthday.

An unbirthday present is one given for no particular reason.  One had been given to Humpty Dumpty in Alice through the Looking Glass.

Purely for medicinal purposes is a common excuse for keeping brandy in the house.

All the trappings of  means all the appurtenances of(Nothing like explaining something with an even more obscure phrase!)  This is concerned with appearances.  Trappings were harnesses.  Does anyone know whether there is a connection with horse-brasses?

A carry-on is similar to a to-do or a fuss.  Carry on also means continue, or it has a literal meaning carry means travel along holding something.  Goods trains carry freight.  People carry luggage onto trains.

A series of films was made with Carry on in the title.  Coincidentally, while I was preparing this post a news item was published referring to one of the actors.

 God gives good gifts.  St Paul wrote to the Christians in Rome about the gift God gives through Jesus.  Romans 5