Ugaritic is the only WS language where *ˁrb fully preserves its (presumably, original) status of the main exponent of the meaning “to enter.” (Kogan 2015: 333)
Ugaritic
ˁrb - to give a guarantee or pledge, stand surety for, leave a deposit
(DUL 180)
ˁrm - a cloak or blanket
(DUL 183, Watson 2007: 81)
in a difficult context (for a totally different interpretation: from ˁrw ‘to be naked’ v. Ford 2002b:190‒191), borrowing from Akk. erimtu ‘a garment’ (CAD E 294) is unprovable (Kogan 2015: 361).
likely related, along with Akk erpetu - ‘cloud’ with metathesis to *ˁapar- ‘cloud’ in continental MSA
probably an ultimate connection to *γarpill- - storm cloud