By surface analysis, under + bygga. Cognate of Norwegian Bokmål underbygge.
underbygga (present underbygger, preterite underbyggde, supine underbyggt, imperative underbygg)
active | passive | |||
---|---|---|---|---|
infinitive | underbygga | underbyggas | ||
supine | underbyggt | underbyggts | ||
imperative | underbygg | — | ||
imper. plural1 | underbyggen | — | ||
present | past | present | past | |
indicative | underbygger | underbyggde | underbyggs, underbygges | underbyggdes |
ind. plural1 | underbygga | underbyggde | underbyggas | underbyggdes |
subjunctive2 | underbygge | underbyggde | underbygges | underbyggdes |
present participle | underbyggande | |||
past participle | underbyggd |
1 Archaic. 2 Dated. See the appendix on Swedish verbs.