1. (verb) appear suddenly

• pop out

2. (verb) erupt or intensify suddenly

• break open
• erupt
• flare
• flare up
• irrupt

1. (verb) give sudden release to an expression

• evince
• express
• show

2. (verb) appear suddenly

• appear

3. (verb) erupt or intensify suddenly

• deepen
• intensify

1. (verb) give sudden release to an expression

• rip out

1. (verb) erupt or intensify suddenly

• burst
• flare-up
• outburst
• eruption
• eruption
• irruption
• irruption
• outbreak
• outbreak