For this mini cryptic, each entry has two clues (not necessarily in this order): one gives the answer, and one speaks to certain changes needed before the answer can be entered.
1A: tabooS INSide / DIE in m[AU]i 4A: CODESIGN - SIGN / APP + END + IX 5A: TAR inside (CHAR)* / SP + corRect + bEE + D 1D: EON right-to-left + L / double definition 2D: UN turned + ED back / keENER GYm 3D: MIE + STY (sides switched) - Eastern / EX in S + TED
Explanation: One of each of the clues solves to an (admittedly rough) homophone indicating that the solver should add/delete a letter from the other answer: SINS ADIEU (add U) = SINUS; CODE APPENDIX (append X) = CODEX; SPREED CATARRH (cut R) = SPEED; SLACKS NOEL (no L) = SACKS; NUDE ENERGY (enter G) = NUDGE; SEXTED MISTY (miss T) = SEX ED
4A: CODESIGN - SIGN / APP + END + IX
5A: TAR inside (CHAR)* / SP + corRect + bEE + D
1D: EON right-to-left + L / double definition
2D: UN turned + ED back / keENER GYm
3D: MIE + STY (sides switched) - Eastern / EX in S + TED
Explanation: One of each of the clues solves to an (admittedly rough) homophone indicating that the solver should add/delete a letter from the other answer: SINS ADIEU (add U) = SINUS; CODE APPENDIX (append X) = CODEX; SPREED CATARRH (cut R) = SPEED; SLACKS NOEL (no L) = SACKS; NUDE ENERGY (enter G) = NUDGE; SEXTED MISTY (miss T) = SEX ED