1 to split up

2 to divide

3 to break up

4 fission

5 schism

1 heaven falls and earth rends (idiom); rocked by a major disaster

2 fig. violent revolution

3 major social upheaval

1 to rip apart

2 to tear

3 laceration

4 rent

1 pit

2 stone

3 nucleus

4 nuclear

5 to examine

6 to check

7 to verify

1 core

2 nucleus

1 all split up and in pieces (idiom); disunity (in an organization)

2 complete lack of unity

3 to disintegrate

4 falling apart

5 to be at sixes and sevens

1 heaven falls and earth rends (idiom); rocked by a major disaster

2 fig. violent revolution

3 major social upheaval

1 to be scared out of one's wits (idiom)

1 in mortal fear (idiom)

1 to have a splitting headache (idiom)