1 to split up

2 to divide

3 to break up

4 fission

5 schism

1 to tear

1 to rip apart

2 to tear

3 laceration

4 rent

1 to split

2 to crack

3 to break open

4 to rend

1 (of dry soil, skin etc) to crack

2 to chap

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)