Can the Absolute be at the same time One and still be defined as existence, knowledge and bliss? Rāmānuja discusses this topic with an opponent in his Śrī Bhāṣya on Brahma Sūtra 1.1.1. The opponent says that if the Absolute brahman is only Oneness, then all attributes would end up as having to be understood only  metaphorically (lakṣaṇā). Rāmānuja replies that this would not be a problem, since contextual meaning (tātparyavṛtti) —which, we understand, includes the possibility of secondary signification (lakṣaṇā)— overrules direct meaning (abhidhānavṛtti):

[Rāmānuja:] This is not a flaw, since contextual meaning overrules even direct meaning. And everyone agrees that the contextual meaning [of the passages regarding the Absolute brahman] is that that to which [the adjectives] refer is one only.

[Opponent:] But it has never been seen that secondary signification regards all words!

[R:] And what follows from that?

Next, Rāmānuja explains that secondary signification is resorted to systematically also by the Prābhākaras, who maintain that within the Sacred Texts (the Vedas) all sentences are prescriptions and that in the world there can be exceptions, in which cases secondary signification steps in:

[…] Those (Prābhākaras) who say that the meaning of a sentence is something to be done (kāryavākyārthavādin) have, in the case of worldly sentences, all words depend on secondary signification. Since the primary (i.e., direct) meaning of the exhortative verbs is just something to be done which was not known before (apūrva), the action to be done (kriyākārya) is understood through them through secondary signification.

In other words, exhortative verbs denote directly that something has to be done. The fact that this something to be done is an action is understood from them only through secondary signification.

And the  primary meaning of the other words, which denote their own meanings  as  connected with something to be done, is [also] connected with something to be done which was not known before. Thus, the fact that they communicate [their meanings] also as connected with an action only depends on secondary signification. Therefore, there is no flaw even if all words are understood through secondary signification for the sake of avoiding a contradiction with the contextual meaning (as suggested at the beginning of this paragraph).

In case of contrast,  the Sacred Texts overrule direct perception and the other [instruments of knowledge depending on it].

Why does Rāmānuja pull in the Prābhākaras? Within Mīmāṃsā, secondary signification is usually banished and only tolerated if it is the only way to avoid meaninglessness. Thus, he needs to convince Mīmāṃsā authors that there is nothing wrong with secondary signification. Of the two subschools of Mīmāṃsā, the Bhāṭṭa Mīmāṃsā is an easy task. In fact, Kumārila Bhaṭṭa has already explained that in both ordinary and Vedic language words directly denote their own meanings and that the sentence-meaning is reached through secondary signification. Instead, the Prābhākara Mīmāṃsā authors might be more difficult to convince, hence the need to show that they also rely on secondary signification, at least in the case of explaining how ordinary language may refer to actions instead of highlighting only the kārya, the “[thing] to be done”.

The translation of kriyākārya is a complex issue. If you are interested in it, please check my 2012 book on Prābhākara Mīmāṃsā (a draft is also available on my page on Academia.edu).  Alternatively, you can read this post (on kriyākārya) and this one (on apūrvakārya) on my previous blog.