-tum

Also known as: the infinitive, tumun

In this lesson, we will learn about the root suffix -tum, which creates uninflected words.

When added to some root that means “X,” -tum creates a word that means “to X.” Here are some examples:

• अहं खादितुम् इच्छामि।
  ahaṃ khāditum icchāmi.
  I want to eat.
  

• एतान् न हन्तुम् इच्छामि।
  etān na hantum icchāmi.
  I don't want to kill them.
  (Bhagavad Gita 1.34)

We almost always use -tum with another verb. Often, we use -tum words to express that someone wants to do something:

• गजः खादितुम् इच्छति।
  gajaḥ khāditum icchati.
  The elephant wants to eat.
  

But there are many other verbs that we can use with -tum:

• गजः खादितुं शक्नोति।
  gajaḥ khādituṃ śaknoti.
  The elephant is able to eat.
  

• गजः खादितुं जानाति।
  gajaḥ khādituṃ jānāti.
  The elephant knows (how) to eat.
  

• गजः खादितुम् आरभते।
  gajaḥ khāditum ārabhate.
  The elephant begins to eat.
  

• गजः खादितुं यतते।
  gajaḥ khādituṃ yatate.
  The elephant tries to eat.
  

• गजः खादितुम् अर्हति।
  gajaḥ khāditum arhati.
  The elephant deserves to eat.
  

And in a more general way, -tum can show the reason that some action was done:

• गजः खादितुं चरति।
  gajaḥ khādituṃ carati.
  The elephant walks (in order) to eat.
  

• गजः खादितुं धावति।
  gajaḥ khādituṃ dhāvati.
  The elephant runs (in order) to eat.
  

Sound changes

When we add -tum, we strengthen the root's vowel to the medium level. As usual, some roots don't use iṭ:

• नी → नेतुम्
  nī → netum
  lead → to lead
  

and others do:

• वन्द् → वन्दितुम्
  vand → vanditum
  venerate → to venerate
  

Otherwise, -tum generally causes similar sound changes to -tvā:

• बुध् → बोद्धुम्
  budh → boddhum
  awaken → to awaken
  

• मुच् → मोक्तुम्
  muc → moktum
  free → to free
  

• गै → गातुम्
  gai → gātum
  sing → to sing
  

Review

-tum is a common suffix that is worth knowing well.