In this study, Syzygium aromaticum extract as a stabilizing and reducing agent was utilized to synthesize copper nanoparticles in the aqueous medium. Various techniques containing UV-Vis. spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy Dispersive X-ray Spectrometry (EDS) were used to characterize the synthesized nanoparticles (CuNPs). On the other hand, the MTT assay was run to evaluate anti lung cancer activity of CuNPs. The crystal size of CuNPs, according to the XRD analysis, was 30.73 nm. Moreover, the uniform spherical morphology ranging from 19.55 to 69.70 nm was detected in the SEM images for the biosynthesized nanoparticles. In the cellular and molecular part of the recent study, the treated cells with CuNPs@Syzygium aromaticum were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung adenocarcinoma properties on normal (HUVEC) and lung adenocarcinoma cell lines i.e. HLC-1, LC-2/ad, and PC-14. In the antioxidant test, the IC50 of CuNPs@Syzygium aromaticum and BHT against DPPH free radicals were 119 and 69 µg/mL, respectively. The viability of malignant lung cell line reduced dose-dependently in the presence of CuNPs@Syzygium aromaticum. The IC50 of CuNPs@Syzygium aromaticum were 443, 500, and 377 µg/mL against LC-2/ad, HLC-1, and PC-14 cell lines, respectively.