aði

aði is a term used in Icelandic grammar to denote the past tense suffix -aði that appears on many regular (weak) verbs. It is not a standalone word in Icelandic; rather, it is an inflectional ending that attaches to a verb stem to form the simple past (preterite). The form derives from Old Norse and is inherited into modern Icelandic as the common past-tense marker for a large class of verbs.

In practice, adding -aði to a verb stem yields past-tense forms such as talaði from tala, meaning I spoke or he spoke, and kastaði from kasta, meaning I threw or he threw. The exact spelling of the ending can vary due to phonological adjustments and the person or number of the subject, and not all verbs use this suffix—strong verbs form past tense through stem changes rather than a fixed -aði ending.

The suffix contrasts with strong verbs in Icelandic, which do not rely on a single past-tense ending and instead change the vowel or the stem to indicate the past tense. Historical variation and dialectal differences may also influence how the ending is realized in speech and older texts.

In educational contexts, -aði is commonly introduced as the standard past-tense marker for many regular verbs and is used in narrative and descriptive pasts. Some verbs do not follow this pattern due to irregularity or strong-verb conjugation, requiring separate memorization of their past forms.

See also: Icelandic language, Icelandic grammar, Icelandic verb conjugation, weak verbs.