An Adûnaic verb appearing as an element in various compounds as -zîr or zîr- (SD/389, 423). The verb was not translated, but its primitive root form ZIR is glossed “love, desire”, so this verb probably has a similar meaning.
Several authors have suggested (EotAL/ZIR, NBA/20) that the verb stem is zir- with a short vowel. However, the vowel is long in the participle form zîrân “beloved”, and there are tentative examples where a verb with a short vowel would retain that short vowel in the agental/participle form: magân “*builder”. I therefore think that the verb stem is likelier to be zîr-.
Carl Hostetter and Patrick Wynne suggested (AAD/25) that it may be related to the Middle-Period Elvish root ᴹ√SER.