The verb 'suffice' in the Germanic languages is of major interest to syntactic reconstruction for several reasons. First, two different, but etymologically related, verbs exist in the early daughter languages with the meaning 'suffice', reconstructable as *ga-nahan and *ga-nōgjan. Second, major inconsistencies are found between the case and argument structure constructions across the two verbs and across the daughter languages, including Nom-Gen, Acc-only, Acc-Nom, Acc-Gen, Dat-Gen and Dat-Nom. These case frames are not particularly compatible with each other, severely limiting the chances of a successful reconstruction. A further scrutiny reveals that the younger verb may also occur as a ditransitive, which complicates matters even further. Here both verbs are reconstructed for Proto-Germanic with different case frames, including how the internal development may, or even must, have been in order for the two verbs and the different case and argument structure constructions to be reconcilable. This study also shows that the lexical semantic meanings range from 'satiate', 'endow' and 'satisfy' to 'be satisfied', 'find sufficient' and 'suffice', all depending on the relevant case and argument structure constructions, calling for a further investigation into the role of argument structure for semantic change with lexical verbs.