Kambaata, a Cushitic language of Ethiopia, has a productive, word-class changing approximative derivation. The process marked by the suffix -lab takes adjectival, nominal and verbal roots as inputs and generates approximatives that belong to the adjective word class, whose members are characterised by their agreement behaviour in the NP. The meaning of the Kambaata approximatives is dependent on the word class of its input. Deadjectival approximatives express a vague, attenuated degree of a property, deverbal forms convey similarity or near-identity in manner, while denominal forms express similarity in nature or function and create ad hoc categories. The sub-meanings are subsumable under an overarching meaning of approximation, understood as deviation from a prototypical realisation. The source of the -lab suffix is a verb ‘resemble’. From a Cushitic perspective, the Kambaata approximative derivation is unique of its kind. No related language is known to have approximative morphology.