adj

• (archaic) Of a person: perverted or insane, originally supposedly due to the influence of the Moon; compare lunatic.
  "VVhat miſerie th' inabſtinence of Eve / Shall bring on men. […] all maladies / Of gaſtly Spaſm, or racking torture, qualmes / Of heart-ſick Agonie, all feavorous kinds, / Convulſions, Epilepſies, fierce Catarrhs, / Inteſtin Stone and Ulcer, Colic pangs, / Dæmoniac Phrenzie, moaping Melanchole / And Moon-ſtruck madneſs, pining Atrophie, / Maraſmus, and vvide-vvaſting Peſtilence, / Dropſies, and Aſthma's, and Joint-racking Rheums."
• (figurative) Showing irrational behaviour, especially of a romantic or sentimental nature; in an entranced or distracted state, especially due to being in love.
  "[…] I, the moon-struck slave of Dora, perambulated round and round the house and garden for two hours, […] blowing kisses at the lights in the windows, and romantically calling on the night, at intervals, to shield my Dora—I don't know exactly what from, I suppose from fire."
• (obsolete except UK, regional) Made physically sick, or (like fish) unsuitable for food, by the supposed effect of moonlight.
  ""Yes, yes, thank God! I am not blind; I was afraid I was moon-struck." "Moon-struck!" uttered Carlos in astonishment. "What do you mean?" "Why, don't you know," answered Antonio, "that sleeping in the open air by moonlight often causes contractions, and sometimes makes persons blind whenever the moon shines?""