ἥτις
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
French (Bailly abrégé)
fém. de ὅστις.
English (Autenrieth)
(ὅ ττι), gen. οὗτινος, ἧστινος, and ὅτ τεο, ὅ(τ)τευ, dat. ὅτεῳ, acc. ὅτινα, pl. neut. ὅτινα, ἅσσα, gen. ὅτεων, dat. ὁτέοισι, acc. ὅτινας: who(so)ever, which(so)ever, what(so)ever, both relative and indirect interrogative; ξεῖνος ὅδ, οὐκ οἶδ' ὅστις, ‘unknown to me,’ Od. 8.28. See ὅτι.
Russian (Dvoretsky)
ἥτις: f к ὅστις.