irregular

US /ɪˈreɡ.jə.lɚ/
UK /ɪˈreɡ.jə.lɚ/
"irregular" picture
1.

not even or regular in shape, arrangement, or distribution

:
•
The coastline is very irregular, with many coves and inlets.
•
He has an irregular heartbeat.
:
unevenasymmetricalerraticdisorderedunsteady
:
regularevenuniform
2.

not conforming to established rules or methods; abnormal

:
•
The verb 'to be' is an irregular verb in English.
•
His attendance at meetings has been very irregular.
:
unconventionalanomalousdeviantunusualaberrant
:
regularstandardnormal