Words

Akkadian
paṣṣu - absent, missing (CDA 268)
No definitive etymology can be suggested.
Akkadian
pašāḫu - to rest, to calm down (CAD P 227, AHw. 840, EDA I 422)

Derived words: mušapšiḫu (a part of a door) (CAD M₂ 259, AHw. 681); pašāḫiš ‘in peace’ (AHw. 840); pašāḫu ‘tranquility’ (CAD P 227); pašḫu ‘resting’ (CAD P 251, AHw. 844); pušḫu ‘soothing’ (SAD I); šupšuḫu ‘calm’ (AHw. 1280); tapšaḫu ‘resting place’ (CAD T 194, AHw. 1322); tapšīḫu ‘relief’ (CAD T 194, AHw. 1323); tapšuḫtu ‘rest, relief’ (CAD T 195, AHw. 1323).
The etymology of the Akkadian verb is not yet fully clarified (Huehnergard 1991a:694). It may be related either to PWS *pŝḥ ‘to rejoice’ or to PCS *pšḥ ‘to be spacious’.

Akkadian
pašāḳu - to be narrow, to be difficult (CAD P 235, AHw. 841)

Derived words: mušapšiḳtu ‘having difficulty (in childbirth)’ (CAD M₂ 259); muštapšiḳtu (multapšiḳtu) ‘having difficulty (in childbirth)’ (CAD M₂ 285); pašḳiš ‘with difficulty’ (CAD P 257, AHw. 845); pašḳu ‘narrow; difficult; dangerous’ (CAD P 257, AHw. 845); pašuḳtu ‘difficulty, hardship’ (CAD P 269); pušḳānu (a person with a characteristic feature) (CAD P 543, AHw. 883); pušḳu ‘distress, constriction’ (CAD P 543, AHw. 883); šapšāḳu ‘constraint, hardship’ (CAD Š₁ 482, AHw. 1176); šupšuḳtu ‘woman having difficulty (in childbirth)’ (CAD Š₃ 327, AHw. 1280); šupšuḳu ‘very narrow, difficult’ (CAD Š₃ 327, AHw. 1281).
This specifically Akkadian root has no reliable Semitic etymology. Cf. perhaps Arb. fašaq- ‘distance between two horns or two teats’.

Akkadian
pašallu - (a kind of gold) (CAD P 233, AHw. 841)
No etymology can be suggested.
Akkadian
pašālu - to crawl (CAD P 234, AHw. 841)
Var. pešēlu. Derived words: pašālatti ‘crawling’ (CAD P 233, AHw. 841); pašultu (a crawling animal?) (CAD P 269).
No etymology can be suggested.
Akkadian
pašānu - (a bird) (CAD P 235)
No etymology can be suggested.
Akkadian
pašar - (a mathematical term) (CAD P 236, AHw. 842)
No definitive etymology can be suggested.
Akkadian
pašāru - to loosen, to relax (CAD P 236, AHw. 842)
Derived words: mupašširu (a profession) (CAD M₂ 210); napšartu (treated grain) (CAD N₁ 316, AHw. 741); napšurtu ‘release’ (CAD N₁ 318, AHw. 741); napšuru ‘forgiveness’ (CAD N₁ 319, AHw. 741); pašartu ‘sale(?)’ (CAD P 236); pašertu ‘undoing’ (CAD P 251); pašīratti ‘secretly’ (CAD P 252, AHw. 844); pāširtu ‘loosener’ (CAD P 252, AHw. 844); pašīru ‘secret’ (CAD P 252, AHw. 844); pāširu ‘dissolver’ (CAD P 252, AHw. 844); pāširu ‘exorcist, dream interpreter; peddler’ (CAD P 253, AHw. 844); pašru ‘loosened, calm, apportioned’ (CAD P 258, AHw. 845); pišīriš ‘secretly’ (CAD P 428, AHw. 868); piširtu ‘release’ (CAD P 428, AHw. 868); pišru ‘interpretation’ (CAD P 429, AHw. 868); puššurtu ‘solution(?)’ (CAD P 545, AHw. 884); tapšīrtu ‘absolution’ (CAD T 194, AHw. 1322); tapšuru ‘ransom’ (CAD T 195, AHw. 1323).
No definitive etymology can be suggested.
Akkadian
pašāšu - to anoint (CAD P 245, AHw. 843)

Derived words: napšaštu (napšaltu) ‘ointment, salve’ (CAD N₁ 317, AHw. 741); paššu ‘anointed’ (CAD P 259); piššatu, piššetu ‘ointment’ (CAD P 430, AHw. 869); pušištu (pušiltu) ‘malt residue’ (CAD P 542, AHw. 1583).
In view of the consistent spellings with ŠV signs in Ebla, the etymological source of pašāšu can be confidently fixed as *pṯṯ. No reliable cognates with this phonetic shape have been detected.

A comparison with Modern Ethiopian *fss ‘to spill, to pour’ is possible.

Akkadian
pašāṭu - to erase (CAD P 249, AHw. 844)

Derived words: pašittu ‘obliteration’ (CAD P 256); pāšittu lit. ‘female obliterator’ (a female demon; an illness; a constellation (CAD P 256, AHw. 845).
The Akkadian verb is hard to separate from *pšṭ in Hebrew and Aramaic, for which two basic meanings can be postulated, viz. ‘to spread, to stretch’ and ‘to strip off, to separate’. The semantic aspects of this equation remain rather obscure: the meaning ‘to efface, to erase’ in Akkadian is not exactly the same as ‘to strip off’ in NWS, whereas the internal NWS derivation from ‘to strip off’ to ‘to stretch’ (or vice versa?) is also far from transparent.

May be related to Arb. bsṭ ‘to spread, to expand with an irregular mutation of labials in Arb. (Kogan 2015:477).