exclamation, burp, belch
噫 centers on a sudden vocal outburst from the mouth: an exclamation, or the bodily sound of a burp or belch.
噫 combines 口 (mouth) with 意, which likely provides the sound. The character expresses sounds made with the mouth, such as exclamations or belches.
The mouth 口 on the left and 意 on the right suggest a sudden sound bursting from the mouth: an exclamation or a burp.
For イ, imagine an exclamation of surprise: 'Ee!' The sound 'ee' cues イ, and it bursts from the mouth 口.