hit-or-miss

• hit-and-miss, hit or miss, hit and miss (UK)

hit-or-miss (comparative more hit-or-miss, superlative most hit-or-miss)

1. (now chiefly US, informal, idiomatic) Inconsistent, unpredictable, erratic; sometimes succeeding and sometimes failing with no apparent pattern.
   • 1919, Robert F. Griggs, “The Great Mageik Landslide”, in The Ohio Journal of Science‎^[1], volume 20, number 8, page 342:

     On the contrary, these cones are made up of materials of all sizes mixed together in the most hit or miss fashion.

• historism