open up

verb

1. (intr) to start firing a gun or guns

2. (intr) to speak freely or without restraint

3. informal,  (intr) (of a motor vehicle) to accelerate

4. (tr) to render accessible

   the motorway opened up the remoter areas

5. to make or become more exciting or lively

   the game opened up after half-time

Idioms and Phrases

Spread out, unfold, as in A green valley opened up before us . [Early 1800s]

Begin operation, as in The new store opens up next month . [Late 1700s]

Begin firing, begin attacking, as in The artillery opened up at dawn , or, figuratively, The speaker opened up fiercely on the opposition . [1930s] Also see open fire .

Speak freely and candidly, as in At last the witness opened up and told what happened . “ Colloquial ; c. 1920]

Make an opening by cutting, as in The surgeon opened up the patient's chest .

Become available or accessible, as in With new markets opening up all the time we hope to see our revenues increase dramatically . [Mid-1800s]

Increase the speed of a vehicle, as in Let's see how fast the car will go if you open it up . [ Colloquial ; c. 1920]

Open the door, let me (or us) in, as in Open up! This is the police . [Mid-1900s] Note that in all of these usages except def. 4 and 7, up serves as an intensifier, that is, it emphasizes the verb open .

Related Words

• advise 
• announce 
• confess 
• declare 
• disclose 
• explain 
• express 
• inform 
• instruct 
• mention 
• notify 
• order 
• report 
• reveal 
• say 
• speak 
• state 
• summon