intransitive verb
1. : to commence firing
2.
a. : to become communicative
b. of a hound : to give tongue
3. : to spread out in or come into view
the road opens up ahead
4. : to turn toward an audience or camera
5. : to launch an offensive especially in competitive sport
open up with forward passes
open up with a series of quick punches
transitive verb
1. : to cut into ; especially : to open surgically
2.
a. : to make plain or visible : disclose
her account opened up a whole new line of investigation
b. : to bring into view
means to place his drive so as to open up the green for his approach — Paul Gallico
3. : to make available
new opportunities were opened up as the population grew
4. : to force (a defense) to spread itself thin
split the line to open up this defense — Jim Tatum