use one's head

present singular third person uses one's head · participle present using one's head · participle past used one's head · past used one's head

1. idiomaticTo think carefully, especially as an alternative to being guided by one's emotions.

   He never—so they agreed—uses his head. He never—I think I have their phrase correct—stops to think.

   1918, Stephen Leacock, “Back from the Land”, in Frenzied Fiction

   2 more examples

   When a girl falls in love, after first using her head to find a suitable mate to fall in love with, it is such a wonderful feeling.

   1957 March 13, Joyce Jackson, “Guide to Dating”, in Toledo Blade, page 35

   Bound by that commitment, he used his head, channeling his rage into a determination to bring the killers to justice.

   2007 January 23, Chris Thornton, “A Belfast Father's Vindication”, in Time

   Synonyms: use one's noggin, use one's coconut

2. humorousTo headbutt.