deiknumi

δείκνῡμι

is used for text book paradigms of - νῡμι verbs

δείκνῡμι and other νῡμι verbs have the following inflections

for Active Present Indicative

Singular δείκνῡμι δείκνῡς δείκνῡσι

Dual δείκνυτον

Plural δείκνυμεν δείκνυτε δείκνύᾱσι

For Imperfect you add ῡν ῡς ῡ υτον etc to ἐδείκν

For Subjunctive take a stem of δεικνύ and add the normal endings

Likewise for Optative

Goodwin's Grammar and other works show all the forms.

The main thing to remember is the u final and to watch how the accents shift

The Infinitive is δεικνύναι and the Participle δεικνύς

In Aorist δείκνῡμι has a First Aorist stem of δείξ and a Second Aorist stem of δύ

The Future stem is δείξ the Perfect δέδειχ and the Pluperfect ἐδεδείχ