Prepositions are words such as to, for, into, without, from etc. They give us information about the role that the nouns and pronouns they stand with play in a given sentence: I give this book to you (indirect object). The book lies on the table (place where). He cut the cake with a knife (instrument). In English, prepositions are numerous and frequently employed, and always stand in front of the noun or pronoun (hence the name pre-position).
Sanskrit, on the other hand, is an inflected language that can draw on case endings to mark the role that a noun plays in a sentence. Thus it only has a small number of prepositions in regular use. These, furthermore, stand behind the noun that they belong to, not in front of it (thus, properly speaking, they are post-positions). The most frequently used prepositions are:
प्रति (+ ACC) ‘towards’: नगरं प्रति ‘towards the city’
सह (+ INSTR) ‘with’: मित्रैः सह ‘together with friends’
विना (+ INSTR, ACC or ABL) ‘without’: भयेन/भयं/भयात् विना ‘without fear’
Related, but far more frequent in Sanskrit, is the use of preverbs, which are added to the front of a verb:
अप- means ‘away, off’ –› अपगच्छन्ति means ‘they go away, they depart’
आ- means ‘in this direction, hither’ –› आगच्छति means ‘he comes’
प्रति- means ‘towards, back to’ –› पुरं प्रतिगच्छसि means ‘you go back to the city’ or ‘you approach the city’
Some of these, such as प्रति, can function both as prepositions and as preverbs, and may then vary in meaning (as a preposition, प्रति expresses the idea of ‘towards’; as a preverb, it can mean ‘towards’, but also ‘back to’). A list of the preverbs employed on a regular basis is given in the Vocabulary section below.
Verbs that employ a preverb are called compound verbs. A few aspects of their use need to be pointed out.