Ansonia teneritas is relatively small; SVL in males <22 mm, in females <25 mm. It is known from Usun Apau and Gunung Hose. The body is slim and limbs are long and slender. Subarticular tubercles are indistinct. The webbing is membranous (not fleshy as in Pelophryne). Parotid glands are absent. The tympanum is visible.

The snout clearly projecting in profile. The head is depressed. Longitudinal interorbital ridges are absent. The first finger is short, not reaching base of tip of second finger when adpressed. There is no sharp tarsal ridge. Warts on the temporal regions are not enlarged. The coloration is olive-green with a contrasting dark brown pattern on head and dorsum. Whitish pattern below the eye on upper lip and some white warts behind jaw joint, on shoulders and flanks. The iris bright red- orange with an irregular network of black reticulations.

Details of reproduction and tadpoles are unknown.