vt to encourage with shouts.
2. halloo ·vt to chase with shouts or outcries.
3. halloo ·noun an exclamation to call attention or to encourage one.
4. halloo ·vt to call or shout to; to hail.
5. halloo ·vi to cry out; to exclaim with a loud voice; to call to a person, as by the word halloo.
6. halloo ·noun a loud exclamation; a call to invite attention or to incite a person or an animal; a shout.