tremulous

adjective2

1. •
   Trembling, quivering, or shaking.

   • From the high tree the blossom wavering fell, / And over them the tremulous isles of light / Slided, they moving under shade: […] — 1847
2. •
   Timid, hesitant; lacking confidence.

   • “You have lived here long?” Felix asked, with tremulous interest, as he took a seat on the bench under the big tree, towards which his new host politely motioned him. — 1891