From Wiktionary, the free dictionary
From head + high.
headhigh (comparative more headhigh, superlative most headhigh)
- Tall so as to reach one's head.
2021, Michael Farris Smith, chapter 40, in Nick, New York, Boston, London: Little, Brown and Company, page 196:The house was painted crimson and a headhigh brick wall stretched out and closed in the backyard and a single light shined in an upstairs window.
