Singularly rhymes with:
irregularly, regularly, circularly, extracellularly, irregularly, particularly, popularly, regularly, spectacularly, circularly, extracellularly, irregularly, particularly, popularly, regularly, similarly, spectacularly
irregularly, regularly, circularly, extracellularly, irregularly, particularly, popularly, regularly, spectacularly, circularly, extracellularly, irregularly, particularly, popularly, regularly, similarly, spectacularly