Ud-

prefix in verbal & nominal comb^n. One half of all the words beginning with u˚ are comb^ns. with ud˚, which in comp^n. appears modified according to the rules of assimilation as prevailing in Pāli

I. Original meaning

“out in an upward direction”, out of, forth; like ummujjati to rise up out of (water), ujjalati to blaze up high; udeti to come out of & go up; ukkaṇṭha stretching one’s neck out high (cp. Ger. “empor”); uggilati to “swallow up” i.e. spit out

The opposites of ud-are represented by either ava or o˚; (see under II. & IV. & cp. ucc-âvaca uddhambhāgiya: orambhāgiya), ni (see below) or vi (as udaya: vi-aya or vaya)

II.

Hence develop 2 clearly defined meanings, viz.

1. out, out of, away from-˚aṇha (“day-out”); ˚agga (“top-out”); ˚āgacchati; ˚ikkhati look out for, expect; ˚kantati tear out; ˚khitta thrown off; ˚khipati pick out; ˚gacchati come out; ˚gamaṇa rising (opp. o˚); ˚gajjati shout out; ˚gilati (opp. o˚); ˚ghoseti shout out; ˚cināti pick out; ˚chiṭṭha thrown out; ˚jagghati laugh at, cp. Ger. aus-lachen ˚tatta smelted out; ˚tāna stretched out; ˚dāleti tear out; ˚dhaṭa lifted out, drawn out; ˚disati point out to; ˚drīyati pull out; ˚pajjati to be produced; ˚patti & ˚pāda coming out, origin, birth ˚paṭipatiyā out of reach; ˚paḷāseti sound out; ˚phāsulika “ribs out”; etc. etc
2. up (high) or high up, upwards on to (cp. ucca high, uttara higher)-: ˚kujja erect (opp. ava˚); ˚kūla sloping up (opp. vi˚); ˚khipati throw-up, ˚gaṇhāti take up; ˚chindati cut up; ˚javati go up-stream, ˚javana id. (opp. o˚); uñña pride; ˚thāna “standing up” ˚ṭhita got up; ˚tarati come out, go up (opp. o˚); ˚nata raised up, high (opp. o˚); ˚nama e-levation ˚nāmin raised (opp. ni˚); ˚patati fly up; etc. etc

III. More specialised meanings

(from elliptical or figurative use) are:

1. ud˚ = without, “ex-”, e.g. unnangala “outplough” = without a plough; uppabbajita an ex-bhikkhu.
2. ud˚ = off, i.e. out of the way, wrong, e.g. uppatha a wrong road, ummagga id
3. ud˚ = out of the ordinary, i.e. exceedingly, e.g. ujjangala extremely dusty uppanduka very pale; uppoṭheti to beat hard

IV. Dialectical variations & combinations

1. Owing to semantic affinity we often find an interchange between; ud˚; and ava˚; (cp. E. break up = break down, grind up or down, tie up or down), according to different points of view. This wavering between the two prefixes was favoured by the fact that o always had shown an unstable tendency & had often been substituted for or replaced by ū, which in its place was reduced to u before a double consonant, thus doing away with the diff. between; ū & u; or o & u. For comparison see the foll.: ukkamati & okk˚ uññā: avañña; uddiyati: odd˚; uḍḍeyya oḍḍ˚; uppīḷeti opīḷ˚; etc., & cp. abbhokirati → abbhukkirati
2. the most freq. comb^ns. that ud˚ enters into are those with the intensifying prefixes abhi˚; and sam˚; see e.g. abhi ud (= abbhud˚) + gacchati, ˚jalati; ˚ṭhāti; ˚namati etc. sam + ud + eti; ˚kamati; ˚chindati; ˚tejeti; ˚pajjati etc.

Vedic ud-; Goth. ūt = Ohg. ūz = E. out, Oir. ud-; cp. Lat. ūsque “from-unto” & Gr.; υ ̔́στερος = Sk. uttara