ˈunder-ˌsucking,ppl.a. [under-1 4 a, b.] a. Sucking from below. b. Sucking down. 1611Speed Hist.Gt.Brit. vii. xxxvii. §2. 335 Y⊇ blossoms of vnder-sucking plants.a1886C. Rossetti Poems (1904) 144/2 Who sinks, uplift from the undersucking silt To set him on Thy rock.